An image projection apparatus and an image projection method are provided. The image projection apparatus includes a projection light source, a scanning module, a reflection mirror and an optical detector. The projection light source provides a projection light beam and the scanning module drives the projection light beam to scan along at least an axial direction. The reflection mirror is located on a scan path of the projection light beam. The optical detector detects the projection light beam reflected by the reflection mirror and generates synchronous signals. The image projection apparatus determines a scanning frequency of the projection light beam according to the synchronous signals.