The application of Software Failure Modes and Effects Analysis (SFMEA) and Software Fault Tree Analysis (SFTA) has obvious defects when applied separately. Difficulties of SFMEA to express logical relationship among failure causes, and possibility of SFTA to omit the top events have direct impact on compensating provision. Thus it needs to take integrated application of SFMEA and SFTA into consideration. This paper discusses the principle of both forward and backward integrated analysis techniques, and the flexile implementation in different phases of software development process. Finally we use a case study to illustrate the effectiveness of integrated analysis techniques and the feasibility of flexible application.