Description/Abstract This research investigated the effect of surface roughness on fluid flow response of rock fractures. Fracture surface roughness could change the fluid flow regime from laminar to turbulent, while it causes the flow properties to deviate from cubic law for smooth channels due to a change in fracture equivalent hydraulic aperture. Hence, the aims were to investigate the potential for assessment of fluid behaviour by studying its surface geometrical properties. Numerical simulations for synthetic flow channels and real rock fractures were performed by fluid flow simulation software (FLUENT) with assuming the laminar flow regime in both 2D and 3D. In this research also, anisotropy in fluid flow behaviour when it travels along different directions and the effect of fracture shearing on flow response were investigated. The outcome results demonstrated how detailed analysis of surface geometry could provide valuable information with respect to surface flow behaviour.