The invention provides a micro-mirror monitoring method and device, a lighting device and a photoetching machine. The micro-mirror monitoring method is used for monitoring the turning angle and surface type of a micro-mirror in real time, and comprises the steps of firstly providing at least two laser beams which are parallel and equally spaced; then obtaining light spots formed by the two laser beams on a photosensitive element after being reflected by the micro-mirror and transmitted by a Fourier lens; then measuring the positions of the light spots, and thus determining the turning angle ofthe micro-mirror according to the positions of the light spots; and measuring the spacing of the light spots generated by the two laser beams, and thus determining the variation in surface type according to the variation in spacing of the light spots.