Probe light pulses are injected into the sensing fiber by a distributed optical fiber vibration sensing system based on the phase-sensitive optical time-domain reflectometer (Φ-OTDR), then the vibration can be recognized and located by measuring the Rayleigh-backscattered light generated during the propagation of light pulses, so the probe light pulse has important effect on Φ-OTDR system performance. The research progress of Φ-OTDR in pulse modulation was introduced, including the impact of optical pulse width, frequency, shape, extinction ratio and other parameters on the system mechanism, and the research progress in the optimization of system parameters such as signal-to-noise ratio, alarm rate, spatial resolution, response bandwidth and recovery of vibration signal waveform by pulse modulation. In addition, this paper provides a new idea to ascend multiple performance indicators of the Φ-OTDR system simultaneously by means of optical pulse modulation to promote the engineering applications of Φ-OTDR.