The micro-dsplacement sensor based on double-layer grating Talbot effect has the advantages of high resolution and anti-electromagnetic interference,however,its accuracy is affected by the fabrication and assembly errors of gratings. In this paper,COMSOL software is employed to simulate and analyze the influence of the fabrication errors (including the line width,thickness and duty cycle of the grating) and assembly errors (including the included angle of layers,included angle of grid lines and grating spacing of double-layer grating) of the gratings.The final results shows that the allowable error of the grating period is less than ±0.1 μm,the influence of the thickness of the grating on the diffraction efficiency is negligible,and the optimal value of the duty cycle is 0.5.In addition,the included angle of layers,included angle of grid lines of double-layer grating also have a significant impact on the diffraction efficiency,the allowable errors of included angle of layers,included angle of grid lines and grating spacing of double-layer grating are less than 1°,0.1° and ±0.1 μm,respectively.The analysis will be helpful to compensate for various types of errors in the future,thereby ensuring high-precision micro-displacement detection system based on grating Talbot effect.