The invention discloses a dynamic sampling-based method for extracting the laser spot. The method comprises the following steps: 1) the position of a camera is fixed, the visual angle of the camera is adjusted to ensure that the projection area is in the vision field of the camera; 2) a projector is used to project a white image on the wall suface, the camera captures the image to obtain the P_SOURCE of the image; 3) the point with the maximum brightness is extracted to ensure that the maximum brightness of the image is about 200 and the brightness saturation is 255; 4) a laser pointer is used to project a laser spot in the image-capturing range of the camera, the camera captures the image to obtain the P_LASER of the image; 5) according to the P_SOURCE and the P_LASER, the color gamut range [LASER_MIN, LASER_MAX] of the laser spot under the condition is generated; 6) the laser spot is extracted according to the generated color gamut range of the spot; and 7) if the intrinsic brightness of the environment changes, the step 1) is performed again.