Judging from the volume of transactions in the international foreign exchange market,the yen has become the third largest foreign exchange currency in the world. The reasons why the yen has become a major international exchange currency are as follows. Firstly,Japan has three basic conditions,namely, economic power,trade power and moderate degree of dependence on foreign trade. Secondly,Japan has completely abolished foreign exchange control and established a highly developed financial market by promoting financial liberalization for a long time,thus creating a good market environment for the internationalization of the Japanese yen. Thirdly,through the channels of euro-yen bond,yen international bond,international direct investment and indirect investment,Japan has become a major net creditor country in the world,and the yen is not only universally accepted in Japan,but also has strong universal acceptance all over the world. Finally,the long-term value stability and low interest rate have made the yen a high-quality safe-haven currency and an arbitrage currency with good price,so that it is favored by international investors. We can learn much from the successful experience of the Japanese yen to promote the internationalization of RMB. We should give priority to the realization of free convertibility of RMB and then consider expanding the use of RMB in international transactions. We should build a highly developed domestic financial market and make it become one of the basic conditions for expanding the international trade of RMB. The stability of RMB value and exchange rate should be maintained to make it become an international asset preferred by international investors.