UWB vehicular radar has the potential to be a powerful tool in improving vehicle safety. The Gaussian monocycle pulse, commonly used in the UWB vehicular radar system, can not satisfy the bandwidth constrains. So a new pulse shape based on wavelet is presented, which selects factors of Morlet wavelet to meet the FCC spectral mask by searching the peak frequency which lies in bandwidth between 22 and 29 GHz. Contrasted to the traditional method, the algorithm changes the searching method from two dimensional random variables to one dimensional random variable. Simulation results show that the method can generate pulse shapes which comply with FCC regulation.