Forest products exhibit natural carbon-storage function and alternative emission effect necessary to mitigate climate change effectively. Carbon flow, which is generated along with forest products trade, has been considered as an important topic of intergovernmental climate negotiations and distribution of climate responsibilities. Based on a case study of harvested wood products (HWP), the Global Forest Products Model (GFPM) and stock change approach are used in this research to simulate and analyze carbon flow of regions and major forestry countries in the trade from 2010 to 2030. Results show that Europe, Asia, and North/Central America are the major regions of HWP trade carbon flow in the world; their corresponding total trade carbon flow will reach 75.9, 43.0, and 33.0 TgC by 2030, respectively. Among these regions, Europe and Asia are the largest and most principal net outflow and inflow regions, respectively; the corresponding net carbon flows will reach 28.2 and 17.3 TgC by 2030, respectively. Developed countries will remain in a dominant position in the carbon flow of HWP trade from 2010 to 2030 and considered as net carbon outflow countries of HWP trade. By contrast, developing countries will be accounted for the net inflow in the carbon flow of HWP trade. Gross trade carbon flow and net trade carbon flow of both groups likely exhibit an increasing trend. In terms of product structure of HWP trade carbon flow, developed countries will focus on exporting sawnwood with higher carbon-storage performance and on importing paper and paperboard with lower carbon-storage performance. Developing countries will experience completely opposite circumstances. However, product structure greatly differs among these countries.