The characteristics of the concealed reception of the passive radar network make it have a advantage in the anti-jamming.This paper applies passive radar to ship formations. First, constructing a passive radar system with different receiving stations and different topological structures. Then, proposed p and q indicators, Evaluated the detection capability of the station topology from anti-interception capability, jamming exposed range of the system. At last, summarized the detection performance when using the particularly number of stations, gave advise on the number of station sites for warship formations.