A following operation system includes a target device and a vehicle body. A control module of the vehicle body is connected with the target device and sends out a first signal. The control module controls the vehicle body to move in a manual or following mode according to a switch signal from the target device. In the manual mode, the user imposes an external force to move the vehicle body. In the following mode, the control module generates a movement signal according to the signal sent back by the target device, whereby vehicle body follows the target device according to the movement signal. When the target device leaves the communication range of the control module, the control module stops the vehicle body and sends out a reminder signal. Therefore, the movement method of the vehicle body is adjustable, and a reminder function is provided.