In the recent year, the banks in Australia developing in a high speed. There are lots of changes happened on Australian bank, especially, the efficiency of bank. The bank efficiency is a key point of bank development. This report will analysis the changes of bank efficiency from there aspects: technical efficiency, cost efficiency and profit efficiency. The main reasons of bank efficiency changes are that scale inefficiency; the ability of transforming; the increase of per capital income; economics of scope; the increase amount of financial services; the development of new financial products and the wildly use of electronic commerce. What is more, the report also mentions the relationship between bank efficiency and stock return. Using the financial leverage ratio model to explain that bank efficiency has the positive effect on stock return of the bank.