This study is conducted to explore the influence of the evolution of shale reservoirs on their fractal dimensions.Specifically，three examples are selected for the case study，namely，the terrestrial shale with low maturity of Yanchang Formation in Erdos Basin，the terrestrial shale with high maturity of Shahezi Formation in Songliao Basin，and the marine shale with high and excessive maturity of Longmaxi Formation in the southern Sichuan region. On this basis，the evolution characteristics of different fractal dimensions are studied by means including X-ray diffraction（XRD），geochemical analysis，and nitrogen adsorption experiments in combination with the Frenkel-Halsey-Hil（FHH）and thermodynamic models. Moreover，the grey relational analysis（GRA）was performed to analyze the controlling factors of fractal dimensions in different evolution phases. The results reveal that the terrestrial shale with low maturity has low fractal dimensions，whereas the terrestrial and marine shale with high maturity has high dimensions. In the marine shale evolved from high maturity to excessive maturity，a high pore volume and surface area have a significantly positive relationship with the pore complexity，but this relationship is not prominent in the terrestrial shale with low maturity. The reason might be that the occluded hydrocarbon causes micropore blocking or covers the surface of pores，which reduces the fractal dimensions. As the evolution increases，the main influencing factor of the fractal dimensions of shale reservoirs gradually changes from the mineral compositions to the total organic carbon（TOC）.