A laser projection system comprising a laser light and a human body detection module is disclosed. The laser light source emits a laser light. The human body detection module detects a reflective light of the laser light irradiated on an object. The human body detection module determines whether the object is a human according to a relationship between several reflectivity indexes of the reflective light. If the relationship corresponds to predefined situation, the human body detection module reduces a laser output intensity of the laser light.