This paper investigates the problem of designing a kind of frequency-phase modulated waveform with low sidelobes. The mentioned waveform has a new structure with both frequency and phase coded. We present the analytic expression of the waveform and formulate an optimization problem to find a sequence of phase codes to suppress the sidelobes of the autocorrelation function. The constraint of sidelobes is constructed by the derived autocorrelation expression. The optimization problem can be solved by the traditional series quadratic programming (SQP) method. The simulation results are given to demonstrate the effectiveness of the mentioned optimization model.