Based on investigation and analysis of aeromagnetic and gravity data, this paper has put forward some opinions about the basement framework and relief as well as structural features of central Ili basin, made some description of the features of geophysical field and , what is more, determined the thickness and distribution of Permian in the western part of the basin, thus providing basis for further oil and gas exploration in the Permian strata. Basides, aimed at finding out the evolution of the basin, the paper has dealt preliminarily with the development of the covering strata.