Based on the multi-fractal theory, an algorithm to determine the minimum residual sum of squares for piecewise fitting is implemented through establishing the area - element model, according to Peruvian Don Javier porphyry copper deposit and the surrounding area surface geochemical data, and the residual sum of squares can be used as the basis to determine the number of scale-free space. The geochemical positive and negative abnormal range within the scope of the study area is delineated. By analyzing the spatial distribution of positive and negative anomalies and combined with the results of statistical analysis of the each element value, the Enrichment and Depletion Regularity of The main metallogenic elements is been Investigated. On that basis, prospecting criterions are established and it is showing that the southeast area of the ore-body is prospecting targets. The effectiveness of the method has been verified by drilling, which provides a new approach for the in-depth analysis of the geochemical data and to prospect surrounding the deposit.