The invention relates to an environment detection method in an unmanned vehicle target search system, which comprises the following steps of S1, creating an unmanned vehicle global environment map andan onboard camera field of view coverage map; S2, performing combined environment search on a target to be searched at a current position, extracting and evaluating edge regions to determine the target point position of the unmanned vehicle in the next step; S3, generating a collision-free desired path, controlling the unmanned vehicle to reach the target point position; and S4, determining whether the target to be searched is located at the target point position, and completing the environment detection if so, or returning to the S1 if not. The method realizes the autonomous environment detection based on edge region guidance in an unknown environment and realizes efficient search for the target to be detected in an unknown region, and a planned travel path realistically reflects the driving characteristics of the vehicle.