The invention discloses a miniaturization lens-free laser three-dimensional imaging system based on a micro-electromechanical system (MEMS) scanning micro-mirror and an imaging method thereof. The miniaturization lens-free laser three-dimensional imaging system adopts a red,green and blue three-color laser as a lighting source, three-color laser output luminous power combines into a bunch of white light to be projected on the surface of an object after modulation, red light components, green light components and blue light components in scattering light on the surface of the object are received by a photoelectric receiver group, and a distance value of a single detected pixel and a range value of three-color light components are obtained by a measuring circuit. A microcontroller calculates three-color luminous value of the single detected pixel according to the range value of the three-color light components, and a three-color real luminous value of the pixel is obtained by using a real-time distance square correction method. The microcontroller controls the MEMS micro-mirror to scan, distance values and three-color real luminous values of all pixels are obtained, a depth image and a gray level image of the object is generated by combination, and a three-dimensional colored image of the object is finally obtained. The miniaturization lens-free laser three-dimensional imaging system needs no optical lens, and is high in imaging resolution ratio, fast in speed, simple in structure and easy to miniaturize.