<p>Rock mass fracture is the key position for engineering stability and underground material transport. Contact deformation occurs under stress, and the traditional calculation method is relative vertical contact (RVC), which does not consider the rotation effect before contact. For surface contact without bottom control, self-adapting deflection contact (SDC) is proposed as a theoretical model for the analysis of fracture surface contact deformation. Considering with the rotation effect, the initial contact point of the fracture will be changed from one point to more points, the initial average aperture size will decrease, and the initial deformation modulus will increase. Under stress, based on the theory of boundary element method (BEM) computation, the SDC contact point will increase, the average contact pressure will decrease, and the average aperture is larger for SDC. Based on Reynolds Equation, the streamline, flow ratio, and seepage pressures are contrasted in both modes. At the same external load and water injection pressure, the fracture has better permeability for SDC. The above SDC mode describes the fracture contact deformation more truly, which is of important theoretical significance for the accurate description of the formation fracture change and the transport of matter.</p>