The effect of substrate temperature on the homoepitaxial growth process of a SrTiO3(001) surface has been investigated using our crystal growth molecular dynamics simulation code. SrO molecules were continuously deposited one by one on the SrTiO3(001) surface terminated by TiO2 atomic plane at 300 K. Two-dimensional and epitaxial growth of a SrO thin layer was observed on the SrTiO3(001) surface retaining perovskite type structure and (001) oriented configuration. However, some defects were constructed in the grown film at a low temperature of 300 K, which is in significant contrast to that at 713 K. In the latter case, a single flat and smooth SrO layer was formed without any defects, which is in good agreement with the experimental results. The self-diffusion coefficient, activation energy for surface migration, and adsorption energy of the deposited SrO molecules on the SrTiO3(001) surface were discussed. A higher migration ability of the deposited SrO molecules at high temperature was found to lead to complete layer-by-layer homoepitaxial growth.