A projection apparatus and a location method for determining a position of a light point on a projection image of the projection apparatus are provided. The projection apparatus comprises a lens, a light detector, a light guide module and a processing circuit. The light guide module is configured to receive the light point via the lens, and to guide the light point into the light detector. The light detector outputs a detection signal to the processing circuit according to the light point within a detection period. The processing circuit determines the position of the light point on the projection image according to the detection signal.