The quality of F track has a critical influence on the safety and comfort of low speed maglev transportation. Therefore, track geometry must be measured termly. And Appropriate maintenance of F track will be carried out according as the measurement results to keep track all right. In order to maintain maglev guideway efficiently, FMS01 is a F track geometry measurement system made by National Univ. of Defense Technology and the first one in China, and it can be operated to measure track geometry fast and accurately, including vertical deviation, lateral deviation, track gauge and level difference when maglev train travel at 20-100km/h. Vertical and lateral deviation can be measured based on inertial principle. The measurements of the 1.5km long line in Tangshan was carried out using FMS01.The experimental results show that maximum error of vertical deviation is less than ±0.7 mm in reference to fine measurement using level gauge and maximum error of track geometries is less than ±0.2 mm in reference to the average of measurements using FMS01.