Stress measuring system of optical materials

The invention relates to a stress measuring system of optical materials. The system comprises a beam splitter prism, a polaroid, a first photoelectric detector, a second photoelectric detector and an external cavity length tuning component. A half-external cavity laser is adopted as a laser. Laser emitted from a first cavity mirror of the laser is vertically incident upon the beam splitter prism. The beam splitter prism divides the output laser into two parts. The two parts of laser are respectively detected and received by the first photoelectric detector and the second photoelectric detector, and a front receiving end of the second photoelectric detector is provided with the polaroid with its light pass direction being vertical to linear polarization direction of the laser output from the laser. Laser emitted from a second cavity mirror of the laser successively passes through a first glass optical wedge and a second glass optical wedge to be emitted onto an optical material sample to be detected. Laser which is reflected by a reflective film at the bottom of the optical material sample to be detected returns along the incipient optical path to the laser so as to modulate the output laser. The stress measuring system provided by the invention can be widely applied in stress measurement of large-area optical glass materials and assembled glass materials.