In order to overcome non-standard prior information processing and poor result credibility during the testability evaluation under small sample test

the method of confirming system testability prior parameters value from expert experience information

subsystem testability information and virtual simulation information was investigated. The testability parameters' prior value was estimated by the weighted fuzzy uncertainty method

subsystem data conversion and Dempster-Shafer (D-S) evidence fusion method based on the similarity measure respectively

according to different kinds of testability prior information. The example analysis shows that the prior parameters value during testability evaluation by the proposed method are lower than that of methods from literatures about 0.8%.