The law and method of CDPF passive regeneration were studied by the experiment and a CDPF passive regeneration control strategy was proposed. The control strategy was combined with engine thermal management to improve the passive regeneration rate. The carbon load calculation model was built in Matlab/Simulink, and the experimental results were verified by the bench test and the vehicle test respectively. The results show that the accuracy of the prediction model of carbon load can meet the requirements of strategy and response degree. Passive regeneration control strategy can meet the function requirements of CDPF carbon load control. When the CDPF assisted passive regeneration control is enabled, bench test runs common working condition of road spectrum. In just 2 hours, the carbon load of DPF reduces from 3.8 g/L to 0.96 g/L. In the vehicle test, the assisted passive regeneration strategy can meet the carbon reduction requirements of CDPF. The carbon load control is stable, and no active regeneration occurs when the vehicle runs for 5 000 km.