To accurately monitor the front position in the process of CO₂ flooding and sequestration, two calculation methods for the front of CO₂ flooding and sequestration were established. According to the fluidity change characteristics in the three regions of CO₂ flooding and sequestration, combined with the response characteristics of fluidity change in the field well test curve at different flow stages, the flow stage of the CO₂ flooding field well test curve was divided, the response time of the CO₂ front on the well test curve was identified, and the calculation formula of the CO₂ flooding and sequestration well test front was obtained through well test analysis. On the basis of the dynamic migration process of CO₂ flooding and sequestration plume, combined with Buckley-Leverett oil displacement theory, the mathematical model of CO₂ flooding and sequestration non-piston displacement was established and solved, and the calculation formula of CO₂ flooding and sequestration non-piston displacement front was obtained. The two calculation methods were applied to the field practice, and the front positions of the pure CO₂ zone and the CO₂-crude oil mixed zone were obtained respectively, and the reliability of the two calculation methods was verified by the numerical modeling method. The results indicate that the relative error between the two proposed CO₂ front calculation and the numerical simulation results does not exceed 15%, meeting the accuracy requirements for field applications. This study provides a new way to solve the problems of high cost and long time for CO₂ front monitoring.