Abstract: This paper introduces the analytical scheme for soil and stream sediment samples from 1:50 000 geochemical survey, with the lowest detection limit for methods and controlling values of accuracy and precision. The quality control of chemical analysis includes the control range of accuracy and precision, control of detected rate, repeatability examine of parallel and abnormal samples, and the final quality evaluation for analysis process. With this method, a great number of soil and stream sediment samples in the mapping area were analyzed, which provided a large number of basic data with good application effect.