In order to monitor forest fires， a high-repetition-rate polarization Lidar system was developed based on the light scattering and polarization characteristics of smoke particles generated during fires. The system consists of subsystems for laser emission， optical reception， echo signal acquisition and processing， and scanning control. To meet the demands for large-scale， high-resolution， and rapid forest fire detection， a high-power， high-repetition-rate laser was selected as the probing source， coupled with a high-resolution gimbal for precise scanning. With a Lidar repetition rate of 5 kHz， the system can perform patrol scanning a forest area with a 10-km radius in 48 minutes at an angular resolution of 1°. To address the challenges of echo signal acquisition and cumulative averaging during high-repetition-rate detection， a novel “readout-accumulation-storage” IP （Intellectual Property） architecture was designed， enabling efficient echo signal processing and improving the signal-to-noise ratio. The completed high-repetition-rate polarization Lidar underwent near-field and far-field simulation experiments， with detected signal peaks corresponding to fire locations. When deployed in Yan’an City， the Lidar successfully detected simulated fires at distances of 5.4 km and 8.1 km， validating the system’s effective detection capability.