There are many new features in modern software development．New demands are needed in software testing，such as more efficient，user—oriented etc．Traditional testing methods are unable to solve these problems．In this paper，the authors describe a new testing strategy to meet these demands，which is called application operating coverage based software testing(AOC)The fundamental analysis tools of AOC are navigation dis gram and event record serials．At the end of this paper，they give an automatic testing tool for AOC．