It is of great significance to study the distribution of geochemical indexes in geochemical fields by means of non-linear approaches. In this paper, a typical multifractal model called the method of moments is applied to study the distribution patterns according to the multifractal spectrum forms obtained based on 20 oil and gas indexes from 2085 soil samples over 2000 km 2 in the southern Aixieke-Sangtamu Region in Xinjiang, China. The results indicate that the major oil and gas indexes helpful for petroleum prospecting have relatively weak multifractality or these indexes are nearly single-fractal ones, whereas the other indexes are strongly multifractal. This property is universal throughout the study region and it is believed to provide insight into the evaluation of petroleum resources.