Heavy-duty diesel trucks (HDDTs) have caused serious environmental pollution in China. Accurate estimation of their pollutant emission characteristics is essential to reduce emissions and associated environmental and public health impacts. We developed localized emission factors and a high-resolution emission inventory of HDDTs in Northeast China, based on on-board test, Guidebook and international vehicle emission (IVE) model. The results show that the total emissions of CO, NO, NO 2 and PM from HDDTs in Northeast China in 2020 were 172.2 kt, 531.5 kt, 11.2 kt and 921.4 t, respectively. In terms of spatial distribution, emissions decreased from the city center to the city fringe. Temporally, the NOx emission variation curves of different types of roads presented a "single-peak" emission characteristic, which was different from the peak of tra c ow. We further developed three emission reduction scenarios to analyze the pollution reduction under different policies. Scenario analysis shows that elimination of HDDTs that follow the old China III emission standard and installing tailpipe treatment devices are the most effective pollutant reduction measure. The reduction percentages for CO, NO, NO 2 and PM ranged from 62.9-83.89%. The results of our study could inform policymakers to devise feasible strategies to reduce vehicle pollution in Northeast China.