Disclosed are a projector and a projection positioning method. The projector includes a projector body, a first ranging sensor, a processor and a focal length controller. The projector body includes a projection lens configured to play projection content of a preset area. The first ranging sensor is provided on the projector body and configured to collect position data of a target object within a projection calibration frame formed by the projection lens. The processor is provided on the projector body and at least configured to calculate area data of an adjusted projection calibration frame based on the position data. The focal length controller is communicated with the processor and configured to adjust a focal length of the projection lens according to the area data to change an area of the projection calibration frame played by the projection lens.