Recently, as cross-strait business trades and investments flourish and communications of people become heavier, the accompanying financial services are increasing. Since the competition of banking industry is very severe and there is limited development opportunity in Taiwan, allowing domestic banks to invest in China is inevitable. As the dateline of opening market to foreign countries becomes closer and closer, foreign banks investing in China accelerate. However, the Taiwanese banks are prohibited to invest in China by the government, and the business advantage is losing gradually. The paper first summarizes financial laws of both China and Taiwan regarding to Taiwan banking industry advancing west toward China and then presents the recent situation of foreign banks over there. Finally, this paper discusses possible ways of Taiwan banks investing in Mainland China.