During the uniaxial planar compression of annealed aluminum alloy, a novel approach to determine surface asperity flattening (roughness Ra) is employed by analyzing the evolution of surface microtexture. With an increase in gauged reduction, surface asperity tends to be flattened, and strain hardening increases. Lubrication can constrain the surface asperity flattening process. Development of surface asperity features shows the obvious dependency on  orientation. In-grain slips contribute significantly to the evolution of surface microtexture. Influence of deformation twins (brass orientation) on the evolution of microtexture is not obvious under our current experimental conditions.