The invention discloses a self-excited atomic magnetic sensor for liquid crystal phase compensation and a magnetic field measurement method, which are used for a magnetometer. The self-excited atomicmagnetic sensor comprises a pumping light path perpendicular to the direction of the magnetic field, a probe light path along the direction of the magnetic field, and a circuit closed loop. The pumping light path sequentially comprises an atomic air chamber, a first polarizer, an acousto-optic modulator, and a laser. The probe light path sequentially comprises a photoelectric detector, an atomic air chamber in the pumping light path, a second wave plate1 / 4, a liquid crystal, a first wave plate1 / 4, a second polarizer, and a laser. The closed loop portion of the circuit comprises a photoelectricdetector, an amplifying comparator, a power driver, an acousto-optic modulator, and a counter. According to the liquid crystal phase compensation scheme, a phase shift caused by a circuit coil can beavoided, a phase shift of a larger range magnetic field can be achieved, and the problem that the circuit is unfavorable in the phase shift is solved by combining a light intensity modulation magnetometer and a self-excited magnetometer, the response speed is high, the liquid crystal phase compensation scheme is suitable for the various atomics, and the application value is high.