This paper integrates international and domestic politic factors to analyze the initiation, negotiation, ratification and implementation of Japan-ASEAN FTA. In the past, Japan implemented the multilateral system, and enjoyed the economic profit brought by the open market, therefore neglecting regional free trade negotiation. However, in recently years, Japanese government also started emphasize on FTA. In November 2002, Japan and ASEAN signed the joint declaration, and agreed to build the free trade area in 10 years. This paper will discuss the reason why Japan started to build the FTA with ASEAN, the difficulties in the FTA negotiation why process, and the fature of Japan-ASEAN FTA in the future.