With the rapid development of electronic and information technology, the degree of integration and intelligence of video tracker is higher, and the difficulty of fault diagnosis and location is also higher. Experience and qualitative analysis alone can not meet the needs of maintenance. In order to improve the efficiency of performance test and fault location of video tracker, a fault diagnosis method of video tracker based on modular design is proposed in this paper, and a detection tooling is designed based on the proposed method. The function and data flow of video tracker are divided through decoupling model, and the fault tree analysis method is used for testing and qualitative and quantitative analysis from top to bottom. Experiments demonstares our designed tooling has high applicability, can simplify the inspection and maintenance process and reduce the difficulty of operation.