Based on introduction of reliability qualification test method of rocket launcher, the essentials and rules used in field reliability statistics test of the rocket launcher were elaborated and two critical problems in determining test scheme were analyzed. In this paper, the solution to these problems and an improved field reliability qualification test method for rocket launcher were was puts forward. This paper can be referred for reliability qualification test schemes with few data for judging trouble, especially when the test fund is not adequate. The experiences are helpful for similar products' reliability qualification test.