Abstract: A new fairly selective, simple and rapidy flow injection analysis for the determination with fluorometry is developed, based on the fluorescence equenching effect of Rhodamine 6G due to formation an unfluorescence ion-association complex. Fluorescence was measured at 555 nm(exciation 350nm).Beer's law is obeyed over the concentration range of 0～80μg/L The method was used to determination silicon in steel sample and copper alloys with satisfactoryresults.