The key to the deterioration of bank slope rock mass in the Three Gorges Reservoir area lies in the continuous expansion of rock mass joints. The fractal theory is used to study the deterioration degree, deterioration crushing phase transition time, and development trend of the bank slope measuring window rock mass in the upper and lower drawdown zone. The main conclusions are as follows： the distribution of rock mass joint deterioration has fractal properties, and the steep and gentle turning point of the Λ(r) curve can be regarded as the lower limit of the REV rock mass size. On the whole, deterioration makes the growth of rock mass joints develop to a more uniform and denser trend, showing the characteristics of dimension increase. Further, the deterioration classification standard is established by using the joints fractal dimension increment △Db. Fractal dimension increment value △Db, the increment of area joint number △Jov, and the variation of geological strength index △GSI satisfy the exponential function relationship. Finally, two joints fractal dimension deterioration evolution modes are proposed. The corresponding evolution prediction and analysis can be carried out by using calculation formula of rock mass deterioration and crushing phase transition time, and the prediction of rock mass deterioration and crushing phase transition time is based on secant estimation. Due to the high statistical stability of fractal dimension Db, it can meet the needs of engineering applications. This research provides a new method for the investigation of bank slope deterioration degree and the prediction of deterioration evolution in the Three Gorges Reservoir area.