As lead-zinc deposits in northwestern Hunan are controlled by strata, the authors chose statistical regularities of constant elements in the ore-bearing layer as the basis of integrated geochemical anomaly extraction and used a stream sediment geochemical dataset. Firstly, three main forms of log-ratio transformation were used to explore the effects of the constant elements data closure problem. On such a basis, the PLS method was employed to study the integrated geochemical anomalies. The results show that data transformed by ilr method have obvious symmetrical statistical features and are much closer to the normal distribution. In contrast with PCA and FA, the integrated geochemical anomalies extracted by PLS method are generally more consistent with such geochemical features of lead-zinc mineralization in the study area as the known ore deposits and the fault distribution, and the results can be explained easier in geological field.