Because of the difference in economic and financial development between countries or regions, the influence of the openness on financial development has uncertainty. This paper makes empirical analysis of panel data of ten countries of China-ASEAN during 1995-2013, and the results show that the openness of trade is as a whole conducive to financial development, that financial openness can boost the development of financial agencies but the impact of stock market development and bonds market development is uncertain, that the decrease of bank centralization degree can promote financial development, that economic growth can significantly propel financial development, and however, the effect of institutional quality on financial development has uncertainty. The reason for uncertainty emergence results not only from big difference in economic and financial development level between each country but also from un-compatibility (un-compatible structure) between trade development and financial openness. As a result, each country of China-ASEAN should actively promote trade openness, suitably open finance, gradually decrease the blockade of vested interests, boost the compatibility between financial openness and trade openness, and strengthen financial cooperation so as to improve financial development between each country and regional financial coordinated development.