Abstract: For the establish of SD rats heat stress model and the testing of physical and chemical indexes. 20 SD rats were randomly divided into two groups, 1 group was the control group, 2 group was the model group, 2 group were heat attacked for 2 h in mould incubator with the temperature 40℃and relative humidity 50% , make heat stress occurred, the control group keep normal breeding, after two hours, observed behavior change, checked death individual, plexued blood by retinal vein , detected the physiological and biochemical indexes，detected the liver Hsp70 expression. The results showed that, compared with the control group, the concentration of K⁺ and Na⁺ were decreased, K⁺ reached extremely significant difference (P＜0.01); the concentration of ALB, HB and TP were decreased, reached extremely significant difference (P＜0.01); the activity of ALT, GOT, ALP, LDH, CK were increased, reached difference or significant difference（P＜0.05 or P＜0.01), the concentration of SOD was decreased, reached extremely significant difference (P＜0.01), the concentration of MDA was increased, reached extremely significant difference(P＜0.01);the expression of Hsp70 was increased, reached extremely significant difference (P＜0.01). The Model group was in accordance with heat stress indications, SD rats heat stress model was successfully established.