There are great differences among the target-s radar cross section values in its different angle territory. A new model about mono radar detect probability and radar network comprehensive detect probability was presented. The model was based on the target-s average radar cross section value in its different angle territory. It adopted two different plans in the computer simulation platform: taking the target-s single average radar cross section value; taking the target-s different average radar cross section in its different angle territory, according to the angle of radar refers to the target. There are differences between the two plans- detect probability results, which prove the model-s rationality. The detect model fits the actual detect situation that radar will detect different radar cross section values from different detect angles. The detect probability result is more accurate which comes from the plan that taking the target-s different average radar cross section in its different angle territory.