The invention discloses a continuous wave radar phase interference angle measuring method based on receiving channel multiplexing, wherein high-precision phase interference angle measurement of low-signal-to-noise-ratio radar echo can be realized on the condition of relatively low resource cost. An antenna array of a continuous wave radar is composed of L angle measuring antennae. An antenna switching control signal is set. A continuous wave signal which is received by each receiving channel is caused to pass through a multiple-to-one switch, thereby generating a time division multiplexing single-channel angle measuring signal. Delay processing which matches a receiving channel delay is performed on the antenna switching control signal, thereby generating a sorting control signal. After signal processing is performed on the time division multiplexing single-channel angle measuring signal, a complex-baseband signal which comprises a same-phase branch and an orthogonal branch is obtained. Through controlling by the sorting control signal, sorting is performed on the multiplex-baseband signal, thereby obtaining L independent pulse modulating receiving signals. After segmented integration, the signals are recovered to continuous wave signals, thereby obtaining L independent measuring signals. Phase locked tracking is performed for extracting carrier phase information and finishingphase interference angle measurement.