In optical alignment, because quantizing and compensating of the coupling relation keeps a problem, the coordinates coupling is usually ignored, resulting in adjusting error in accurate optical adjusting. Through modeling and simulation, the coupling relation of each adjusting freedom of a multidimensional precision optical adjusting frame is analyzed in detail. Through decomposed transformation of each adjusting freedom, the coupling relation between each adjusting freedom is compensated and corrected. Test result shows that: by using this method, the error between expected optical adjusting value and actual mechanical adjusting value can be reduced effectively, and more accurate optical adjusting is achieved.