A laser ranging system based on high speed pseudorandom modulation and photon counting technology is developed. 1550 nm fiber laser modulated by 10 order M sequence pseudorandom code and InGaAs/InP single photon detector with three-stage thermo-electric cooler are implemented in the system. The ranging performance is demonstrated using the optical fiber delay method indoor. Under condition of the laser modulation frequency of 622 MHz, the pseudorandom sequence length of 1.64 μs and the detection efficiency of 10%, the signal-to-noise ratio of 22.6 dB and ranging accuracy of 0.95 cm are obtained with -76.1 dBm input signal average power. This demonstration is useful for developing practiced system.