Abstract: The natural philosophical conception that" the geological process and spatio-temporal structure are the essence and crux of geological phenomena" proposed by the author can be used to classify the geological science as four major academic disciplines: the composition and structure of the earth materials, the geological process, the geological field and the evolution of the geosystem. These four major academic disciplines correspond to the nine important basic geological issues and associated complex theoretical problems (Table 2). In this paper, the author applies the complex theory of geological science"the dynamicsof the self-organized critical processof geological process— the fractal growth of geosystems at the edge of chaos" proposed by the author himself to the research into the nine important basic geological issues, with an emphasis on the relatively deep and brief analysis of the nature, theory and research method of the major basic theoretical problems. The purpose of the paper is to understand the geological sciences, old and renewed frequently, from the new pointof view of the complexity of geosystem considered as the basic problem of geological sciences, to raise the study of basic geological problems to the level of the nolinear science and the theory of complexity and to complete the transformation of the geological science into a precise science, with an expectation to make a breakthrough in geological process.