In the present paper the authors designed a vehicle-based remote sensing system using simulated platform and presented a new method of concentration calibration of natural gas pipeline leakage remote sensing. By investigating the performance of different distance, different material, different angle of topographic back scatter and different scan speed, a good coincidence was achieved between experimental results and theoretical results. The system can realize the remote detection of low-level methane concentration at a velocity of 53.3 km·h-1, and the detecting distance is about 70 m with the minimum detectable sensitivity being 28.9 ppm·m. The research result shows the feasibility in the application.