In order to accurately grasp the connotation of the two test schemes of fixed number censoring and sequential censoring, this paper makes an in-depth analysis from the perspective of method principle and characteristics. The characteristic quantity probability models of the two schemes are proposed, and the application scope of the two schemes is revealed from the mechanism. The results show that the analysis provides convenience for the establishment of test scheme in the reliability qualification test of success-failure type products, and has guiding significance for the test organization and implementation.