Introduction: Air walker is the most popular outdoor fitness equipment in Taiwan neighborhood park. The movement during air walker exercise is similar to elliptical trainer and treadmill, but no pervious study explore the exercise intensity. Therefore, the purpose of this study was to compare the stride length and moving speed during air walker, elliptical trainer and treadmill exercise. Methods: Seven young male were recruit as subjects. The displacement of marker placed on the lateral of the right fifth metatarsal was captured by eight high speed cameras, and the maximum was represented the stride length. The stride length of natural walk was measured first with 50RPM cadence and then the stride length during air walker, elliptical trainer and treadmill exercise were measured with a random sequence. The moving speed was calculated from the product of stride cadence and length. Results: There was no significant relationship between the stride of natural walk and air walker. The moving speed of air walk was significantly lower than the treadmill, and higher than elliptical trainer but no significant. Conclusions: The sequence of exercise intensity from high to low was treadmill, air walker and elliptical trainer. The movement of treadmill was most similar to natural walk, and the exercise intensity of air walker was much closed to elliptical trainer but the stride length was not easy to be control steadily.