Embodiments of this application disclose a quantum signal detection method and a quantum signal detection apparatus. The method includes: splitting a received optical pulse sequence into a first pulse sequence and a second pulse sequence that are in orthogonal polarization, where the signal pulses are quantum signal pulses; obtaining information about the reference pulses; generating local oscillator light; splitting the local oscillator light into first local oscillator light and second local oscillator light whose intensities are the same and that are in orthogonal polarization; performing homodyne detection on the first pulse sequence and the first local oscillator light, and performing homodyne detection on the second pulse sequence and the second local oscillator light, to obtain homodyne detection results; and obtaining regular components of the signal pulses in the optical pulse sequence according to the homodyne detection results and the information about the reference pulses.