The formula of maximum velocity attenuation is derived by using the damping vibration model of springs and slider on the air track，then the damping constant of the air track is deduced. Moreover，the damping constant is inferred from the perspective of quality factor and the method can be considered as an approximation of maximum velocity attenuation method if the damping is small enough. By two designed damping vibration experiments on the air track，the damping constants corresponding to above-mentioned different algorithm are obtained by using measured amplitude，cycle and light shielding time，et al. and the results agree well with each other. Furthermore，the video of moving slider is recorded by playing slowly the video，the attenuated vibration amplitudes and the corresponding damping constants are obtained by using the method of maximum amplitude attenuation. The results show will agreement with those values obtained from the methods of maximum velocity attenuation and quality factor. Therefore the proposed methods to measure the damping constant are proved to be reliable from another point of view. Such methods are practicable and easy to operate in experiment，also the results are tested to be reliable.These proposed methods have provided new ways of thinking to measure the damping constant.