This experiment was conducted to evaluate the safety of high doses of sodium sulfate supplementation in laying hens diet by determining performance, egg quality, hymnological indices and histopathological changes. Four hundred and fifty 20-week-old Hy-Line white laying hens with similar body weight and laying rate were randomly allocated to 5 groups with 6 replicates per group and 15 birds per replicate. Birds were fed basal diets supplemented with 0 (control), 0.3% (the recommended available dose, RAD), 0.6% (two fold of RAD), 1.5% (five fold of RAD) and 3.0% (ten fold of RAD) sodium sulfate for 10 weeks, respectively. The results showed as follows: 1) dietary sodium sulfate supplemental levels had no significant effects on daily egg mass, average egg mass, average daily feed intake, laying rate, the ratio of feed to egg (P>0.05). 2) Compared with the control group, 0.3% and 0.6% groups had a trend of improving egg quality (P>0.05); and compared with 0.6% group, the egg quality of high dose groups (1.5% and 3.0%) was significantly decreased (P0.05). 4) Compared with the control group, 0.3% and 0.6% groups had no significant effects on the contents of glucose, uric acid, creatinine, total protein, albumin, usea nitrogen, total bilirubin and the activities of glutamic-pyruvic transaminase, glutamic-oxalacetic transaminase, alkaline phosphatase in plasma (P>0.05); compared with 0.6% group, high dose groups (1.5% and 3%) significantly increased plasma glutamic-pyruvic transaminase activity (P<0.01). 5) Dietary sodium sulfate added levels in excess of 1.5% could damaged major organ tissues. It is indicated that dietary sodium sulfate supplemental level at 0 to 0.6% is safe in laying hens diet.