Abstract: The resonant energy transfer process of ν₃ vibration energy for ²³⁵UF₆ and ²³⁸UF₆ isotopic molecules was studied by long distance collision theory, and the curves of resonance function with energy difference were obtained. The calculated result shows that the width of resonance function rises with the increase of temperature. In addition, the resonant transfer probability and rate were calculated under different temperatures, and it is found that they decrease with the increase of temperature and the translation of ²³⁵UF₆ and ²³⁸UF₆ isotopic molecules can reduce the resonant transfer probability and rate. These values can provide a reference for actual separation of uranium isotopes.