In order to timely extract protein compounds from Sheep Placenta,investigation of ultrasonic -assisted extraction was carried.The entire experiment was carefully designed and optimized with response surface method (RSM).A second quadratic equation for protein extraction was finally obtained.Factors,such as extraction temperature, solid-liquid ratio,extraction time and their corresponding relationships were investigated.Results showed that the effectiveness order of four factors is as follows:solid-liquid ratio > extraction time > extraction temperature.The optimized extraction conditions were solid-liquid ratio > extraction time > extraction temperature.Under the optimal conditions,the extraction rate of protein from Sheep Placenta reached to 53.17%.