Abstract: The carbon isotope (¹²CO/¹³CO) separation has a separation coefficient of only 1.007, which has typical characteristics of severe separation conditions and long equilibrium time. In order to reduce the operational risk of industrial devices, the theoretical prediction of the dynamic process of ¹³C isotope enrichment is an urgent problem to be solved in industrial technology research. Therefore, the dynamic simulation of carbon isotope separation by CO cryogenic rectification was carried out by using Aspen Dynamics. Through the simulation, the abundance distribution of ¹³C isotope was obtained under the conditions of total reflux, concentration and continuous rectification operation, and the visualization of the abundance change of the ¹³C isotope in the two dimensions of space and time was realized. On the other hand, comparing the dynamic simulation values with the experimental data, the results show that they are agree well, and the relative errors of the enrichment equilibrium abundance and equilibrium time are both less than 15%, which indicate that the accuracy of the dynamic simulation calculation method of ¹³C isotope for cryogenic rectification separation is verified, which can be further used to theoretically predict the abundance enrichment process in the production plant of high abundance ¹³C isotope.