Abstract: This paper deals with the problem concerning geochemical discrimination of tectonic settings of rocks in order to diminish the wrong diagnoses and to improve the geochemical approach to the tectonic study The essential relation between the geochemical characteristics of a rock and its tectonic setting is discussed,so that the discriminating approach can be used more reasonably Then the optimum principles for selecting indicator elements and discriminating methods are suggested and the examples are given.For the sake of overcoming am biguties of the discriinations,a synthetical study of various rocks in a rock suite and of syntectonic rock suites is proposed.