The invention relates to a vehicle searching method and system based on user-defined features. The method includes the steps of firstly, extracting features of each vehicle in a vehicle image database shot by a monitoring camera and storing the features; secondly, searching for the vehicle, satisfying the user-defined features, in the vehicle image database shot by the monitoring camera and feeding back the searching result. The system comprises a vehicle image data reading device, a vehicle area positioning device, a vehicle feature extracting device, a vehicle feature storage device, a vehicle searching device and a searching result displaying device. According to the vehicle searching method and system, diversified searching methods can be provided, a user can search for the vehicle according to the user-defined features in the practical situation, the number of images which are manually confirmed by personnel who handling cases is greatly lowered, labor and materials are effectively saved, the case handling efficiency is greatly improved, and very good social benefits and economic benefits can be produced.