After analysis of the L-level pulse-position-width modulation (PPWM) scheme′s power spectrum,strong spectral lines in the PPWM sequence are found,which are not good for the propagation of the sequences. In this paper,the PPWM modulation scheme is modified,and a new modulation scheme,L-level pulse-width-position modulation scheme (PWPM) is proposed. This scheme lowers the peak value power,scatters the power spectrum,and at the same time has the same power efficiency,bandwidth efficiency and packet error rate as PPWM modulation scheme.