Aiming at the problem that the range and accuracy of low-power laser ranging radar are difficult to balance, a high-performance laser radar ranging system based on FPGA is designed. The system first uses the 14-order M-sequence pseudo-random code to modulate the emission laser at a frequency of 100MHz, and uses dual-port BRAM ping-pong read and write to realize the accumulation of echo photons and restore the echo signal. Then the distance measurement information is obtained through correlation calculation to establish the echo probability model, and the centroid algorithm is used to improve the accuracy of the distance measurement. Finally, a prototype of the radar system is built. The range error is stable at ±2cm when the distance is measured in a 100-meter space environment; when the optical fiber delay method is used to measure the equivalent target of 14.8km, the range accuracy is better than 0.1m. The experimental results show that the system can improve the ranging accuracy when the laser modulation frequency is lower, effectively reduce the difficulty of data processing, and finally realize long-distance high-precision lidar ranging.