Monitoring method, device and system

The invention provides a monitoring method, a device and a system. A user interface is displayed in a display unit and provided with multiple seat blocks corresponding to multiple seats. An image sequence is acquired by image-sampling units arranged at all positions of space. A face identification algorithm is executed to the image sequence for determining whether the image sequence has the human figure of a user. If the image sequence has human figures, an eye-movement tracking algorithm is executed to the image sequence. Furthermore, marking movement is correspondingly performed to the all seat blocks based on whether the user stares at the assigned direction.