The present invention mainly discloses a laser spot detecting and locating system for use in a computer projection system, mainly comprising: a video recorder and a detecting module. The video recorder is used to capture a projected image provided on a projection screen by a projector and a laser spot provided on the projection screen by a laser pointer. Thus, during commercial presentation or classroom teaching, presentation processes and contents of a presenter and moving traces of the laser spot would be simultaneously recorded by the video recorder. Furthermore, by immediately converting the coordinate of the laser spot to a screen coordinate in a displayed image of a host computer, a mouse cursor can be simultaneously moved to the corresponding screen coordinate with the motion of the laser spot.