In order to achieve fast and high-precision measurement and analysis of stress birefringence in optical materials and optical components， this paper proposes a method for the two-dimensional distribution measurement of stress birefringence based on based on dual photoelastic modulators cascade difference frequency modulation. Two photoelastic modulators operating at different frequencies are cascaded to form a novel polarimetry. The retardance and fast axis azimuth of the stress birefringence are loaded into the modulation signals. Employing digital phase-locked technology， the fundamental and differential frequency harmonic terms are extracted， and then the two parameters of stress birefringence are solved out. According to the principle analysis， the system is developed， and the initial offset value of the system are calibrated. A wave plate is used to measure accuracy and repeatability， and the stress birefringence distribution measurement experiment is completed with a BK7 glass sample. The experimental results show that the repeatability of fast axis azimuth and retardance is 0.01° and 0.02 nm， respectively， and the measurement time of a single point data is less than 200 ms. The scheme realizes high-speed， high-precision and high-repeatability stress birefringence measurement. The method demonstrate the ability to measure the two-dimensional distribution of stress birefringence. This provides an effective means for the analysis and evaluation of birefringence measurement of optical materials such as wave plates， glass or crystals.