Selective oxidation has evolved into a key technology in fabrication of high-performance vertical cavity surface emitting lasers (VCSELs). The oxide layers have been pursued to form current apertures and index guiding. However, there exists considerable controversy whether the selective oxidation follows a linear or parabolic growth rate. Oxidation experiments have been done at different temperatures for the two ring groove and perforated ring mesa structures employed in VCSEL. Results show the influences of geometry of mesa structures on the oxide growth rate depend on temperature. Reasonable theoretical analysis is given.