A laser frequency stabilization system for the space integrated path differential absorption (IPDA) lidar is developed. The gas cell is made of the hollow-core photonics crystal fiber (PCF) filled with the CO2 and the absorption line around 1.57 μm is used as the laser frequency reference. The frequency modulation spectroscopy technique is used to stabilize the laser frequency. The impact of the pressure of CO2, the modulation frequency and depth on the error signal′s slope is simulated, and the optimal parameters are given. The computed results are coincident with the measured results. At last, the performance of the laser frequency stabilization is shown, and the suggestion for further improvement is given.