Abstract: The main purpose of this paper is to characterize the disintegration features and driving mechanism of red-bed mudstone under different pH value chemical solutions. The Jurassic red-bed mudstones were sampled from the central Sichuan Basin and statically soaked in pH=3, 5, 7, 10, and 12 solutions for soaking-dehydration cycles. The disintegration process, degree, and changing characteristics of red-bed mudstones were carried out through slake durability index(I_dN),disintegration small particle index(L_dN),fractal dimension(D_s),disintegration ratio(D_r),standard basis entropy(S_b), and surface energy dissipation. The driving mechanism of red-bed mudstone disintegration was revealed from particle microstructure, ion changes, and energy dissipation. The results show that the small granules at a diameter of 0.075~1.25 mm, middle granules at a diameter of 1.25~5 mm, and coarse granules at a diameter of 2~10 mm are clustered in neutral solution(pH=7),alkaline solution, and acidic solution, respectively, at the beginning of the disintegration process. However, the fine granules at a diameter of <0.075 mm are dominant in alkaline solution during the middle and late stages of the disintegration process. The fractal dimension(D_s) is the most suitable for describing the particle distribution of red-bed mudstone disintegration, followed by the standard basis entropy(S_b)index, which can both comprehensively describe the particle distribution during the disintegration process. Based on the energy dissipation theory, the single incremental surface energy of red-bed mudstone was largely influenced by the acidic-alkaline chemical solution. The vibration of single incremental surface energy was increased with the increasing acidity or alkalinity of the solution. The disintegration intensity of red-bed mudstone in the early disintegration cycle under different pH values was as follows: neutral>alkaline>acid, whereas it changed in the middle-late stage of the disintegration cycle to: alkaline>acid>neutral. The red-bed mudstone disintegration was driven by the comprehensive physical and chemical effects of weakening particle connection, mineral fracture dilation, clay mineral expansion, mineral dissolution, and ion exchange.