Aiming at the need for generating complex waveforms, a periodic optical arbitrary waveform signal generation scheme based on polarization multiplexing modulation is proposed. By carefully adjusting the modulation index, radio frequency offset,and bias phase shift of the quadrature phase shift keying (QPSK) modulator, the modulators on the two orthogonal polarization states can output optical intensities in the form of sine and cosine harmonic superpositions in the Fourier series, respectively.When these optical intensities are combined, a functional waveform with precisely controllable amplitude and phase can be obtained, and it also has the characteristic of tunable functional waveform signal output. The simulation results show that when the root mean square error is less than or equal to 0.05, this scheme can generate three typical waveforms: a symmetric factor adjustable (20%~80%) ramp wave, a duty cycle adjustable (30%~100%) triangle wave, and a half-duty cycle adjustable(20%~80%) ramp wave. This verifies the feasibility of the proposed solution.