A small-sized vehicle-mounted projector light system including an illuminating module having a light source, a collimating lens and a film arranged in sequence, and an imaging module; the imaging module includes a curved reflector being a concave mirror with positive focal power, and a first imaging lens. The main optical axis of the illuminating module passes through the reflective surface of the curved reflector, on one side of which the first imaging lens is positioned. The invention ensures an appropriate size of an one-way dimension, no consequence of the limited space within automobile structure during installation and design, and conveniency for arrangement; the curved reflector has positive focal power and can perfect focusing, not only ensuring good projection effect, but also decreasing the number of lenses with positive focal power in the system, and effectively reduce the volume and weight of the system.