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Hydro-chemical erosion has a great effect on the micro-structure morphology and macroscopic mechanical properties of the rock mass. In this paper, direct shear test system was used to study the hydro-chemical effect on the shear strength characteristics of limestone fractures. Besides, morphology parameters of the fracture under different chemical solutions were also analyzed through three-dimensional laser scanning and electron microscope imaging. Experimental results showed that after hydro-chemical erosion, the profile mean square root deviation S q , the profile area ratio R s , the profile peak point density S pd increased, while the slope mean square root S dq decreased. Combined with scanning electron microscope (SEM) images, it is found that due to the hydro-chemical erosion, the roughness of limestone fracture surface, the discreteness of height distribution of the asperities and the JRC 2D values increased, but the slope of asperities decreased. There was a good exponential relation between the decrease percentage of limestone internal friction angle and soaking time, and a logarithmic relation between the decrease percentage of cohesion and soaking time. According to the gray correlation method, the influencing factors were ranked in descending order as follows: normal stress, soaking time and pH values. In addition, the JRC 2D value had a negative linear correlation with internal friction angle and cohesion of limestone fracture.