The laser intensity stability counts for the performance of Nuclear Magnetic Resonance Gyroscope (NMRG). We switch to attenuate the fluctuation of laser intensity with the aid of an opto-electric modulator and feedback control. The Liquid Crystal Variable Retarder (LCVR) has a sharp edge over its counterparts such as AOM and EOM benefiting from its compact size, low operation voltage and large clear aperture. In this paper, we demonstrate a LCVR based laser intensity stabilization system designed for a NMRG prototype. The setup mainly compromises of two crossed linear polarizers, a LCVR, a polarized beam splitter, a photo detector and a digital servo control unit. The intensity of a small portion of laser split by the PBS is detected by the photodiode and then fed into the servo control unit. It compares the current laser intensity with the setpoint value, generates a proper control signal under the supervision of the built-in algorithm and drives the LCVR to change the incident laser polarization state, and hence the output laser intensity. In addition, we derive the formula of the relative output laser intensity with voltage, which helps to design the control algorithm. Finally, the long-term stability of the system reaches 0.038% in a 4-hour continuous measurement.