The purpose of this paper is to examine the impact of WTO membership on Mainland China's industrial growth and economic development. We found that, being a member of WTO, it would benefit Mainland China's economy in such areas as export expansion, capital inflow increases, urging economic reform and readjusting industrial structure. On the other hand, it might lead to structural unemployment, decrease of economic independence, reduction of significant effect of macroeconomic policy and a wider range of economic fluctuations. Among industries, agriculture, electric products, automobiles and some infant industries might encounter some disadvantage and difficulties. On balance, China would obtain net economic gains in the long run by joining WTO.