To address the problem of sensor-based gait cycle detection method, which needs high cooperation of users. Vision-based method is used to develop an accurate gait cycle detection algorithm. Inspired by the idea of frame difference, a novel gait representation feature, namely frame difference temporal and spatial (FDTS) feature is designed. FDTS contains the temporal and spatial information of gait. Thus it can accurately present all states of gait cycle. A new toe-off detection algorithm is first proposed based on FDTS. Then a gait cycle detection method is presented based on the toe-off detection algorithm. Experiments on the public dataset demonstrate the state-of-the-art performance of the method.