A correction method combining internal corner optimization and external scanning error compensation is proposed to address the scanning distortion problem in the oscillator type laser direct writing grating system.The geometrical optical model of the oscillating mirror system is established with the grating grid distance of 10μmas the target.The scanning error is analyzed,then the oscillating mirror turning angle is optimized,and further curve fitting compensation is performed for the oscillating mirror,with the error at the coordinate point(100,10)reduced from 0.936mm,1.912mm to 0.148μm,0.0296μm.The results show that this method can meet the accuracy requirements of vibrating mirror type laser direct writing grating in short distance.