Abstract: A focus following method based on a motion gravity center, a storage medium and a photographing system are provided. The focus following method includes the following steps: S1, acquiring video data captured by a camera within an initial time period; S2, acquiring video data with only a living object within the initial time period; S3, acquiring a motion gravity center image from the video data with only the living object according to a motion gravity center library; and S4, calculating an initial motion direction and an initial motion speed of the motion gravity center image within the initial time period. According to the present disclosure, the calculation amount is greatly reduced, the complex data is simplified, focus following based on the motion gravity center under poor hardware conditions can be can achieved, and requirements of low-cost and mass-production hardware can be satisfied.