The invention provides an optical function signal generator synthesized by multi-wavelength harmonic frequency time domains. The optical function signal generator comprises a multi-wavelength multifrequency mode-locking laser module 1 and a phase and amplitude control synthesis module 2, the multi-wavelength multifrequency mode-locking laser module 1 is a mode-locking laser provided with more than two optical oscillation loops, and the structure includes more than two optical annular branch circuits. Each annular branch circuit can produce photon radiofrequency signals with different wavelengths and different harmonic frequencies and output the signals to the phase and amplitude control synthesis module, and the phase and the amplitude of the signals of each branch circuit are adjusted via the phase and amplitude control module so that desired optical function waveform signals can be finally synthesized. According to the optical function signal generator, the generation and separation of the harmonic frequency of the photon radiofrequency signals are flexible, phase and amplitude control of the signals is accurate, the signal waveform quality is high, the system stability is good, the operation is easy and convenient, and an incoherent light system is employed so that interference introduction and noise disturbance are avoided.