In order to reduce the particulate and polycyclic aromatic hydrocarbon emissions， the effect of biodiesel and particulate trap on particle and polycyclic aromatic hydrocarbons emissions was studied on a multi-cylinder turbocharged biodiesel engine with continuous exhaust regeneration. Results show that the diesel particle emissions present in two forms namely nucleation mode and aggregation mode and its particle sige has a multi peak feature. Using biodiesel has little effect on the nucleation mode particle number concentration， but can make the aggregation mode particle emissions have a clear downward trend with the biggest drop up to 94.6% after using a continuously regenerating particulate trap system. The nucleation mode particle number concentration in diesel particle emissions accounts for more than 60%， and can be further increased up to 95% after burning biodiesel at the test conditions. The continuously regenerating particulate trap system has a higher collection efficiency for aggregation mode particles with， the maximum efficiency of 96%， which will be decreased after burning biodiesel， due to the increased nucleation mode particle number concentration clsing biodiesel can effectively reduce most of polycyclic aromatic hydrocarbons emissions， but test results show that chrysene can not be reduced but increased. The joint use of biodiesel and continuously regenerating particulate trap system can make the phenanthrene， pyrene and benzopyrene etc， six kinds of exhaust pollutants fell even more.