Abstract: R/S analysis is a kind of fractal method to describe and evaluate the complexity of 1-dimension parameter series,based on research of theoretical analysis and practical experiment,this paper discussed about the capability of R/S analysis in describing vertical reservoir heterogeneity and fracture development,and through discussing the difference of reservoir geologic characteristics embodied by different log curves,this paper demonstrated the feasibility of using the fractal dimension difference between AC and GR log curves to evaluate fracture development quantitatively. This method can effectively eliminate the lithological influence but highlight the characteristics of fracture, it has a novel pattern theoretically and shows much better evaluating effects than that of single series analysis.