This experiment was investigated to study the effects of the source and level of dietary protein on the composition of jejunal fluid in growing pigs. A 4×4 Latin square design was adopted and 4 health pigs with similar body weight were selected from 8 jejunal cannulated pigs. Four different diets such as corn-soybean meal diet, low protein corn-soybean meal diet, corn-soybean-rapeseed-cottonseed meal diet and low protein corn-soybean-rapeseed-cottonseed meal diet were given to cannulated pigs according to experimental period and pig number in Latin sheet. There were 15 days in each experimental period, including 10 days in pre-feeding period and 5 days in sampling period. The chyme samples were collected at the time of 09:30, 13:30, 17:30 on the 1st, 3rd and 5th day of the sampling period. The supernatant of the chyme was collected after centrifugated at 4 ℃, and then stored at －70 ℃. The digestive enzyme activities and ion concentration of jejunal fluid were determined. The results showed that there were no significant effects of dietary protein source under the condition of normal protein level and low protein level on the activities of trypsin, chymotrypsin, lipase, and amylase, and the concentrations of Na+, K+, Cl－, Ca2+, Mg2+ and pH in the jejunum fluid of growing pigs (P>0.05). The dietary protein level also did not affect the activities of trypsin, chymotrypsin, and lipase amylase, and the concentrations of Na+, K+, Cl－, Ca2+, Mg2+ and pH in the jejunal fluid (P>0.05). In conclusion, the composition of jejunal fluid from growing pigs can adapt to the dietary protein level and source.［Chinese Journal of Animal Nutrition, 2010，22（5）:1220-1225］