Abstract: This study aimed to calculate and analyze the carbon storage in China’s in-use harvest wood products (HWP) carbon pool, predict the development trends of the wood products carbon pool, and provide data support and theoretical reference for future research on HWP carbon accounting in China. The carbon storage of in-use HWP in China was caculated by employing the stock change approach, production approach, and atmospheric flow approach within the framework of the IPCC 2019 guidelines. Additionally, principal component analysis (PCA) is employed to identify the main influencing factors. Combined with ARIMA time series model and BP neural network model, the future trends of carbon storage in HWP was predicted. (1) From 1990 to 2022, the carbon storage in the HWP carbon pool in China increased year by year. Under the stock change approach, the carbon stock reached 1166.84 Tg in 2022, and the average annual change of carbon storage was 41.83±9.99 Tg from 2006 to 2022. Under the production approach, the carbon stock reached 830.97 Tg, with an average annual change of 27.65±8.07 Tg. Under the atmospheric flow approach, the average annual change in carbon stock was 11.88±4.76 Tg. (2) With the influence of various factors, the carbon storage of China’s HWP was expected to continue to increase in the future, but the growth rate would gradually slow down. In 2060, the predicted carbon storage of China’s in-use HWP was expected to reach 2075.4 Tg, which was 1.78 times that of 2022. China has a tremendous capacity for carbon sequestration in its in-use HWP carbon stocks, and the carbon storage is primarily influenced by economic factors. The growth rate of carbon storage is expected to slow down in the future. Under the carbon peaking and carbon neutrality goals, it is necessary to consider adopting relevant policy measures to address this trend.