It is difficult to form a set of aircraft maintenance outline meeting the requirement of airworthiness for every aircraft manufacture. This article uses the widely applied method, MSG-3,to depict the objective,process,analysis method and result of the structure MSG-3 analysis, followed with the airframe maintenance as an example. This article gives the readers a rough idea about the application of MSG-3 and the method of analysis and requirement of civil aircraft maintenance. The readers are also expected to learn maintenance analysis method gradually in their daily works and yield more economic and social benefits in their further works.