In this paper, we construct a path of economic integration in the Asia-Pacific Region, which is based on RCEP, fully considering India’s return, integration and development with CPTPP and the joining of other countries in the Asia-Pacific Region. The standard static GTAP model is used to predict the economic effects of each integration stage for this path. As the simulation results show, the expansion of integration scope can bring more positive macroeconomic effects to member countries, but the excessive reduction of export prices may lead to the decline of export volume or the deterioration of terms of trade for individual member countries. The trade volume of Chinese industries participating in integration will generally increase. But because the trade growth within the scope of integration is less than the trade reduction outside the scope of integration, the trade volume of some industries will decrease. In addition to animal husbandry and other service industries, the output of other industries participating in integration in China may decrease due to the decline of domestic sales or exports in different integration stages. Therefore, China should actively promote economic integration in the Asia-Pacific Region and seize development opportunities by strengthening cooperation among regional countries in the process of integration. Meanwhile, sound industrial policies need to be formulated to effectively avoid the negative effects of integration.