To build an effective model for effectiveness evaluation is the premise to study the anti-stealth detection of bistatic guidance radars. The detection coverage coefficient and the guaranteed precision coefficient are defined. The detectable area and the guaranteed precision area are calculated by the mesh generation method. The simulation results show that the anti-stealth efficiency coefficient is higher when only considering detection or tracking and the efficiency evaluation data are reliable when considering both of them. The rationality and effectiveness of the model are validated.