1∶50000 regional stream sediment geochemical data contain much information of prospecting. Thus

geochemical anomaly identification of stream sediments is very important. Based on the geological survey in the fields

the anomaly lower limit of 1∶50000 regional stream sediment geochemical data of the Wendi Sheet was determined by using statistical methods and fractal methods

then superimposed with the delineation results and mineral occurrence. The research shows that the anomaly lower limits of Au

Ag

Cu

Pb

and Zn are 1.62 ng/g

0.12 ng/g

22.59 μg/g

104.00 μg/g

and 77.73 μg/g respectively by statistical methods

and 8 ng/g

0.325 ng/g

220 μg/g

460 μg/g

and 2240 μg/g respectively by fractal methods. The spatial superposition of the delineation results and mineral occurrence is better by fractal methods. The fractal methods in determining the anomaly lower limit can be more effective in reducing the scope of anomalies caused by nonmineral. It can reduce the useless anomaly inspection and improve the efficiency of prospecting.