The invention discloses a phase sensitive light time domain reflection system based on dual homologous heterodyne coherent detection, and the system consists of a laser, a coupler, an AOM (acoustic optical modulator), an EOM (electro-optic modulator), an erbium-doped optical fiber amplifier, a filter, a circulator, balance detectors, power dividers, and a data collection card. The balance detector 1 enables the beat frequency signals of received modulated light and local oscillation light to be converted into AC signals, and the balance detector 2 enables the beat frequency signals of received Rayleigh light and local oscillation light to be converted into AC signals, wherein the frequency mixing of the AC signals is carried out through the power dividers 1 and 2, and the outputted AC signals are converted into digital signals through the data collection card, and the processing of the data signals are carried out in a computer. The system carries out the tracking of the drift of frequency and phase changes in a detection arm through a beat frequency signal which is generated by an interference reference arm and does not contain vibration information, can effectively avoid a distortion phenomenon of a detected signal, obtains the stable vibration signal intensity and frequency information, and improves the recognition rate of a vibration source.