The requirements in determination of elements for geochemical samples are different with diverse tasks, as demonstrated by the different requirements for regional survey and for reconnaissance. During the reconaissance as well as the detailed investigation stage, the prospecting work is confined to a comparatively small area, the types of ore likely to be found are quite limited or are predictable, and the elements to be analysed are accordingly fewer (about 20) in number. The relatively crowded measuring networks for the reconnaissance are designed mainly to delimit the inner zones of the anomalies which have markedly high contents and contrast values of elements. Therefore element determination in this stage requires less precision and accuracy than that in regional survey stage. In contrast, the regional survey on the scale of 1:200,000 aims at detecting regional geochemical anomalies characterized by low intensities, low contrast values and vast covering areas. Moreover,as a means to acquire basic geochemical data, its working method involves doing geochemical work according to map areas and then constructing a nationwide geochemical map by piecing together the obtained areas maps at a reduced scale. The correlation and peicing together of adjacent map areas demand considerably high sensitivity and accuracy. In regional survey,determination ought to be made for all elements, including the rare elements, that are likely to form independent ore deposits, and for accompanying elements which may serve as indicators. Not only has the regional geochemical prospecting been widely used in mineral exploration, but it provides increasing quantities of valuable geochemical data for such research fields as regional geology, natural xegionalization,environmental protection,and farming, forestry as well as animal husbandry. At present, 39 elements can be analysed, including the major characteristic diagenetic elements. Some preliminary ideas have also been put forward in this paper as to the suitable measures to be adopted for satisfactorily completing the determination of regional geochemical samples under the present conditions of chemical analysis in China.