The purpose of this study was to investigate temporal and spatial variations, and moments of the lower extremities of gait while playing the game with smartphone under different curb-heights. Ten male elementary school students(from 10 years to 13 years old) participated in this study. Twelve infrared cameras(Oqus-500) and two force plates(9260AA) were used for collecting data and these were processed via Visual 3D software. In conclusion, with or without smartphone and with different curb-heights, the spatial and temporal parameters of walking were not the same and coefficients of variations were not consistent. The maximum joint moments of the lower extremities with or without smartphone were not statistically significant but those of hip and ankle joint were statistically significant with regard to the different heights of the curbs.