Abstract: Choosing four different resistance peppers and inoculating phytophthora capsici when it’s in 8 leaves. The changes of Pro、MDA and dissolubility sugar content and the relations to the resistance to phytophthora Blight of Pepper are studied after inoculating phytophthora capsici in different resistance peppers. The result shows that the growth velocity and accumulation of Pro、MDA and dissolubility sugar content are the critical material in biological activity which determined the peppers resistance to phytophthora blight. The varieties that the content of Pro and dissolubility sugar are higher and the content of MDA are lower , the resistance of them to phytophthora blight are stronger. On the contrary , The variety that the content of Pro and dissolubility sugar are lower and the content of MDA are higher , the resistance of them to phytophthora blight are weaker.