This study was conducted to investigate the effects of dietary protein level on the growth performance, whole body and muscle common nutritional components and serum biochemical indices of Pacific white shrimp (Litopenaeus vannamei) during juvenile shrimp and grow up stages, in order to determine the protein requirements of Pacific white shrimp during juvenile shrimp and grow up stages. Fish meal, wheat gluten meal, casein and gelatin as the main protein sources were used to formulate six experimental diets at various protein levels (29.31%, 33.19%, 37.11%, 41.45%, 45.58% and 49.03%, respectively). A total of 720 shrimp with an initial body weight of (0.52±0.01) g and 540 shrimp with an initial body weight of (7.93±0.03) g were used as experimental animals in test 1 (feeding test for juvenile shrimp stage) and test 2 (feeding test for grow up stage), and were randomly assigned to 6 groups with 3 replicates per group and 40 (test 1) or 30 (test 2) shrimp per replicate (bucket), respectively. The test 1 and test 2 lasted for 56 and 42 days, respectively. The results of the test 1 showed as follows: with the dietary protein level increasing, the weight gain rate (WGR) and specific growth rate (SGR) were firstly significantly increased (P<0.05) and then tended to be stable (P>0.05), while the feed conversion ratio (FCR) had an opposite trend; when dietary protein levels were 37.11% to 49.03%, the protein efficiency ratio (PER) was significantly decreased (P<0.05) with the dietary protein level increasing; there were no significant differences in survival rate (SR) and hepatosomatic index (HSI) among all groups (P>0.05); the condition factor (CF) in 29.31% group was significantly lower than that in other groups (P<0.05). There were no significant differences in the contents of whole body and muscle dry matter and whole body crude protein among all groups (P>0.05); the content of whole body crude lipid in 37.11% group was significantly higher than that in 45.58% and 49.03% groups (P<0.05); the content of whole body ash in 29.31% and 41.45% groups was significantly higher than that in 33.19% and 37.11% groups (P<0.05); the content of muscle crude protein in 41.45% group was the highest, and significantly higher than that in 29.31% and 49.03% groups (P<0.05); the content of muscle crude lipid in 29.31% group was significantly lower than that in other groups except 37.11% group (P<0.05); the content of muscle ash in 33.19% group was significantly higher than that in 37.11%, 41.45% and 49.03% groups (P<0.05). There were no significant differences in serum total protein (TP) content and aspartate aminotransferase (AST) activity among all groups (P>0.05); serum total cholesterol (TC) content in 33.19% group was significantly higher than that in other groups (P<0.05); serum triglyceride (TG) content in 41.45% and 49.03% groups was significantly higher than that in 29.31% and 33.19% groups (P<0.05); serum superoxide dismutase (SOD) activity in 45.58% group was significantly higher than that in other groups (P<0.05); serum phenol oxidase (PO) activity in 41.45% and 45.58% groups was significantly lower than that in other groups (P<0.05); serum alanine aminotransferase (ALT) activity in 37.11% group was the lowest, and significantly lower than that in other groups (P<0.05). The results of the test 2 showed as follows: with the dietary protein level increasing, the trends of SR, WGR, SGR, FCR and HSI were consistent with the results of test 1; the PER was continuously decreased with the dietary protein level increasing, and that in 29.31% and 33.19% groups was significantly higher than that in 41.15%, 45.58% and 49.03% groups (P<0.05); there was no significant difference in CF among all groups (P>0.05). There were no significant differences in the contents of whole body dry matter, crude lipid and ash and muscle crude lipid and ash among all groups (P>0.05); the content of whole body crude protein in 29.31% group was significantly lower than that in other groups (P<0.05); the content of muscle dry matter in 45.58% and 49.03% group was significantly higher than that in 29.31% and 41.45% groups (P<0.05); the content of muscle crude protein in 45.58% and 49.03% groups was significantly higher than that in 29.31%, 33.19% and 37.11% groups (P<0.05). Serum alkaline phosphatase (AKP) activity in 45.58% group was significantly higher than that in 29.31% and 33.19% groups (P<0.05); serum SOD activity in 45.58% group was the highest, and significantly higher than that in other groups (P<0.05); serum PO activity in 37.11% group was the lowest, and significantly lower than that in 29.31%, 33.19% and 49.03% groups (P<0.05); there was no significant difference in serum ALT activity among all groups (P>0.05); serum AST activity in 37.11% group was the highest, and significantly higher than that in 29.31%, 33.19% and 45.58% groups (P<0.05). With the SGR as an evaluation index, regression equations which fitted by broken-line models show that the optimum dietary protein requirements of Pacific white shrimp during juvenile shrimp and grow up stages are determined to be 38.6% and 36.8%, respectively.