Abstract: Matched filtering and dechirp processing are the common methods in wide band imaging radar. They both obtain equal resolution in theory, but perform differently in practical application. This paper starts from the principles of the two methods, and analyzes the distortion of system by dividing it into two portions: the periodic part and the nonperiodic one. The simulation result shows that the method of matched filtering processing performs better than dechirp processing when considering sidelobe suppression and range-resolution and signal noise ratio. The performance of matched filtering is improved with compensation of amplitude and phase distortion. Analysis based on real data proves the effectiveness and efficiency of the proposed strategy of analyzing. The conclusions of this paper can be referred to in the system design of wide band imaging radar.