In this work, the process of oxide removal from the InSb (001) surface was studied in-situ by high-energy electron diffraction in vacuum and under an antimony flux. The dependence of the oxide thickness on the annealing temperature was obtained. It has been found that the antimony flux slows down the process of oxide removal due to the oxide formation reaction. The oxide removal process was described by a system of kinetic equations, the activation energy of oxide decomposition was determined.