Abstract: In order to understand the relief effects of Chinese veterinary medicine summer-expelling and heat-resisting powder on heat stress of pregnancy sow, 14 one-month-old pregnant sows with 2nd-3rd fetal times were selected and randomly divided into control group （basic diet） and summer-expelling and heat-resisting powder group （supplementing 1 kg summer-expelling and heat-resisting powder per 800 kg feed） according to the principle of similar litter weight and fetal times. There were seven sows in each group. The related indices of heat stress were determined. And the test lasted for 8 days. The results showed that the respiratory frequency of sows in summer-expelling and heat-resisting powder group decreased 3.57 times/min than that in control group. And the body temperature in summer-expelling and heat-resisting powder group decreased 0.99 ℃than that in control group. There was no significant difference of respiratory frequency between summer-expelling and heat-resisting powder group and control group（P>0.05）. The average body temperature in summer-expelling and heat-resisting powder group is significantly lower than that in control group （P<0.05）. The number of healthy piglets per sow in summer-expelling and heat-resisting powder group was increased by 10.52% than control group. The number of diseased piglets in summer-expelling and heat-resisting powder group was decreased by 5.49%than control group. The results showed that summer-expelling and heat-resisting powder under the conditions of high temperatures could reduce the body temperature of pregnant sows, increase the number of healthy piglets and decrease the number of diseased piglets. Therefore summer-expelling and heat-resisting powder had good anti-stress effects.