Tea seed saponin is a kind of natural nonionic surfactants with strong properties such as foaming, decontamination, emulsification, solubilization and wetting. Tea seed saponin was extract from tea seed cake by Microwave-assisted alkaline ethanol solution. On the basis of single factor test, the extraction process was optimized by response surface method. The mathematical model between pH value, ethanol concentration and microwave power was established to determine the optimum technological conditions for extraction of tea seed saponin. The results showed that the optimum conditions for tea seed saponin extraction were as follows: ethanol concentration, 73.35%, extraction temperature, 60℃, extraction time, 8min, pH, 9.07, microwave power, 613W, and liquid to solid ratio of 9:1(V/m). Under these conditions, the extraction yield of tea seed saponin was (21.83?0.05)% (n=3) and the purity was 74.1%, which better performance than the conventional water extraction method and ethanol extraction method.