A new concept is put forward in this paper, i. e. the geochemical characteristic elements of geological structure. Classification was made and diagnostic criteria were established for various structural geochemical characteristic elements. On such a basis, they were defined individually. It is pointed out that, in the inference and interpretation of data obtained in regional geochemical survey, we should find out geological significance of various sorts of characteristic elements and use such significance as the guiding train of thought so as to obtain more geological information.