To the patrol searching problem of antisubmarine patrol aircraft using radara radar searching probability model was presentedwhich considered the scanning width of radar searchingthe submarine exposure rate and detection avoidance rate.Based on thisthrough analyzing the patrol line station and relative movement of antisubmarine patrol aircrafta general patrol searching detection probability model was built up by adopting area equivalent method.Finallythe influence of searching timelength and station position of patrol line on radar detection probability was analyzed by simulation.The results showed that:1) the area equivalent model can better solve the patrol searching probability calculation problem of antisubmarine patrol aircraftand 2) the radar detection probability increases with the searching timebut it tends to a special valueand the maximum detection probability is not high.