Severe attenuation by earth absorption and low S/N ratio exists in western China's desert areas.In order to improve the seismic exploration quality of geological targets,the authors put forward a nonlinear sweeping signal design method based on reflection frequency characteristics of target strata to enhance reflection data signal-to-noise ratio of purpose layers.According to characteristics of reflection data frequency spectrum and exploration mission requirements of major purpose layers,the expected frequency spectrum characteristic curves are designed,which are used as distribution relationship between sweeping frequency and energy and applied to controlling the dwell time of sweeping frequency.Then,nonlinear time-frequency relationship is computed and nonlinear sweeping signals are obtained.This method highlights the anticipated dominant frequency energy of sweeping signals and optimizes the seismic wave frequency spectrum of vibrator outputs.Forward modeling and single shot seismic record tests have verified the correctness and validity of this method.Good results are obtained through application tests.