The invention relates to a laser interference system used for measuring a micro roll angle surrounding the linear displacement direction. The laser interference system comprises a laser source, a polarized light-splitting prism, two quarter wave plates, a corner prism, a wedge-angle prism, a wedge-angle reflecting mirror, a polarizer, a photoelectric detector and a phase meter; the laser source generates incident beams with stable frequency and provides a stable reference signal source simultaneously; the incident beams pass through the wedge-angle prism twice under the actions of the light-splitting prism, the quarter wave plates and the corner prism, and are correspondingly reflected by the wedge-angle reflecting mirror twice and sent out by the polarized light-splitting prism; by the interference of the polarizer, the photoelectric detector receives and generates an electric measuring signal, and the micro roll angle of the wedge-angle reflecting mirror fixedly connected with a measured piece can be measured by phase comparison between the phase meter and an electric reference signal. The invention has the advantages of simple structure and high measurement precision, and can bewidely applied to geometrical precision measurement and metering base creation in the fields of military projects, spaceflights, digital control machine tools, and the like.