A numerical reservoir model was built using Computer Modeling Group's GEM simulator to study the process of carbon dioxide (CO2) huff-and-puff in the Bakken tight formation. The influences of injection rate, production time, and soaking time on the incremental oil recovery factor (IORF) were studied systematically, as was the utilization efficiency of CO2 during the whole production process. The results showed that higher injection rates are preferable to lower ones, and the huff-and-puff process works best with a soaking time of 0 days. The production time of each cycle could be optimized for a specific case to maximize IORF, and CO2 efficiency was found to decrease with increasing number of cycles. This study may shed light on how to optimize the CO2 huff-and-puff process and therefore achieve the best enhanced oil recovery performance.