The invention relates to a time sharing laser frequency stabilizing system used for a nuclear magnetic resonance gyroscope, and a method thereof. The frequency of a laser device can be coarsely adjusted through temperature control by TEC for driving the laser device. A fedback laser device current is obtained through minimally modulating the driving current of the laser device and through carrying out signal processing by using a photoelectric detector to receive an optical signal of the laser device going through the gyroscope in order to realize accurate frequency control. The nuclear magnetic resonance gyroscope works at a high temperature, a PWM pulse generator is used to generate a heating signal in order to control the temperature of the gyroscope, and the heating signal influences the laser signal to decrease the frequency, the stability and the precision, so a period of non-heating time is additionally delayed after generation of a heating pulse signal. Temperature control of the nuclear magnetic resonance gyroscope is carried out in the heating signal time quantum, and laser frequency stabilizing control of thenuclear magnetic resonance gyroscope is carried out in the non-heating time quantum. The method can avoid affection of the frequency stabilization precision of laser due to influences of a magnetic field generated due to the heating signal on the output result of the photoelectric detector.