Abstract: The structure of folding unit,the forming of fold as well as the classification of folding machine were analyzed.According to the analysis of the relative location and direction changing character of folds,the decomposition of folding pattern was investigated,and the complicated folding pattern was decomposed as a combination of a series of ordinal parallel folding patterns.The mapping relationship between the folding pattern and folding path was analyzed,and the path selecting principle to improve the using rate of foreside folding units was proposed.On this basis and by means of the matching rule of folding unit,a matching method of folding units to optimize the structure of a folding machine was put forward,and the process and course of the presented method were illuminated by a example.