The Jidong oilfield complex fault block heavy oil reservoir is characterized by small and broken fault blocks, strong reservoir heterogeneity which permeability coefficient of variation is 0.67 and abundant bottom water energy. It is in the “two low and one high” development stage of low recovery, low single well production and high water cut. During carbon dioxide huff and puff, carbon dioxide is easy to lower carbon dioxide utilization efficiency in order to gas channeling by the dominant percolation plug. So the technical idea of CO2 stimulation technology assisted by plugging agent was put forward. The plugging agent which had best static performance consisted of 5% modified starch, 5% acryl amide, 0.05% cross-linking agent and 0.1% initiator. The plugging rate of shutoff agent to high permeability, media permeability and low permeability sand pipes was 99.2%, 97.1% and 91.0% respectively, showing good plugging ability. A CO2 physical simulation model was made by the natural quartz sand in laboratory to study the technology of CO2 enhanced oil recovery technology assisted by plugging agent. The experimental result showed that the oil increment effect was higher than the effect of single CO2 injection technology. Then plugging agent is injected into water area, CO2 is injected into oil area, which is good for oil contact with CO2 and reverse displacement, so the effect is the best. Since 2020, the application of CO2 EOR technology assisted by plugging agent in heavy oil reservoir has been carried out in 932 wells of complex fault block heavy oil reservoir, the oil increment effect is obvious and all cumulative quantity is 364,800 tons.