Based on predecessors’ work, this propose the concept of degenerate test set (DTS) and an approach that performs test generation and redundancy elimination in the light of the special requirement of verification of the secure operating system. This approach is secure state transition-based for the first time and can generate an efficient test set by reducing the redundant system state transitions and similar properties with model checkers in the test case generation. Furthermore, it discusses the validity of the DTS when only some cases of the set fail and improve the DTS generation algorithm. The experiments prove that this approach can reduce the size of test set efficiently.