[en] The life-cycle analysis (LCA) is conducted with a combination of real-time fuel consumption rate data for diesel/liquefied natural gas (LNG) heavy-duty vehicles (HDVs) in China, actual provincial diesel/LNG HDV population data, and a life-cycle inventory database for the Tsinghua-LCA Model (TLCAM) specified for the context of China. The results indicate that direct energy consumption and the life-cycle energy use (MJ) of an LNG HDV are approximately 7.4% and 6.2% higher than that of a comparable diesel HDV, whereas an approximate 8.0% reduction in the life cycle of GHG emissions is estimated if diesel HDVs are replaced with LNG HDVs in China. Due to the increasing use of LNG as an HDV fuel in China (i.e., approximately 4.6 billion cubic metres of natural gas in 2015), the accumulated diesel fuel substituted with LNG was approximately 16 million tons, which generated a GHG emission reduction of 6 million tons of CO₂ equivalent in the HDV fleet from 2006 to 2015. Given that the HDV fleet contributed approximately 6.1% of all GHG emissions in China in 2015, growing the LNG HDV population can increase GHG emission reduction by an approximate range of 6.5–9.1 million tons of CO₂ equivalent by 2020. - Highlights: • A bottom-up model for HDVs fleet is set up to measure energy use and GHG emissions. • Both direct and life-cycle energy and GHG emissions of HDVs fleet are analyzed. • About 8% reduction rate of LC GHG emissions occurred from diesel to LNG. • The diesel saved by LNG trucks was about 16 million tons from 2006 to 2015 in China. • GHG reduction can be about 8 million tons of CO2 eq. by 2020 for China’s HDV fleet.