Laser power stabilization systems with liquid crystal variable retarders have been employed in miniaturized atomic gyroscopes for the merits of low power consumption and easy integration. However, the long-term power drift of the system output with ambient temperature significantly decreases the long-term performance of atomic gyroscopes. Here, we demonstrated a method of dynamic closed-loop control based on the combination of optical power drift and ambient temperature modeling. For a continuous 45 min operation within an ambient temperature variation range of 23.7-25.3 °C, the relative Allan deviation of the output optical power was decreased by one order of magnitude from 2.29 × 10-4 to 3.35 × 10-5 after 100 s averaging time. The long-term stability of the system was significantly improved. In addition, the scheme requires no additional thermal control device, preventing the introduction of extra electromagnetic interference, which is desirable in a miniaturized atomic gyroscope.