The invention discloses a three-dimensional coordinates based skin state comprehensive evaluation method using a projection integral function, and belongs to the technical field of cross fusion of skin science and system science. The evaluation method comprises: firstly, establishing three-dimensional coordinates of an index position set, a test part set and a fuzzy evaluation set; secondly, for evaluation standards given by field experts, proposing the projection integral function to perform interpolation integral operation on test data of a test part, performing secondary interpolation integral on a projection index dimension, and expressing progressive uncertainty of a skin state evaluation grade by adopting fuzzy membership degree; and finally, calculating and determining the skin state comprehensive evaluation grade through a fuzzy matrix. According to the method, a determining result can reflect a skin state comprehensively and objectively, so that the comprehensiveness of evaluation is improved and the objective accuracy of the result is improved; and reference significance is provided for the use of testers to products such as cosmetics and the like.