Abstract: Due to the small thermal neutron absorption cross section of ¹¹B isotope, high abundance ¹¹BF₃ is regarded as an important ion implanted gas and P-type doping source, and is mainly used in semiconductor material manufacturing process to significantly improve the anti-radiation interference ability of semiconductor devices. In order to achieve the optimal design of the high-abundance ¹¹BF₃ isotope separation process, the mechanism of chemical exchange separation of ¹¹BF₃ isotopes was analyzed firstly, and the results show that the difference of intermolecular forces is responsible for the isotope separation. Then, the relative molecular weight and saturated vapor pressure data of isotope molecules were supplemented by self-defined components, and the parameters of the extended Antoine equation were regression extended in the Aspen Plus commercial chemical process simulation software. The process model of ¹¹BF₃ isotope separation based on Aspen Plus was established. RStoic reactor module was used for complexation and cracking reaction calculation, and Radfrac strict rectification module was used for exchange process calculation. Since the separation coefficient calculated by using NRTL-RK thermodynamic method was the closest to the experimental value, NRTL-RK thermodynamic method was selected for calculation in the exchange tower. In the complex tower and the cracking tower, the gas-liquid exchange process was not considered, so NRTL thermodynamic method was used. Next, based on the two sets of experimental data, the Murfree plate efficiency was used to correct the model in Aspen Plus, and the relative errors between the two sets of simulated and experimental values are -2.69% and 0.91%, respectively. It shows that the modified model can describe the process of ¹¹BF₃ isotope separation well. Finally, according to the established mathematical model, the effects of theoretical plate number, reflux ratio and column top pressure on the ¹¹BF₃ isotopic abundance at the top of the exchange column were analyzed. The results show that the decrease of the column top pressure, the increase of the reflux ratio and the increase of the theoretical plate number are all beneficial to the ¹¹BF₃ isotopic abundance. The maximum abundance of the exchange tower reaches 99.95% when the column top pressure is atmospheric pressure, the theoretical plate number is 720 and the reflux ratio is 300. The results of this paper can provide a theoretical basis for the subsequent optimization design. Subsequently, the 11BF3 isotope separation process model established in this paper can be further used to conduct multi-objective comprehensive analysis of investment cost, operating cost and abundance.