Abstract: Pinus sylvestris var.mongolica is one of the main native plantation species in Hulunbuir Sandy Land. Understanding the response of biomass carbon density of Pinus sylvestrisvar.mongolicaplantation to changes of climatic factors is important for rational management to enhance carbon sequestration. We set three 30 m×30 m plots in plantation with stand age of 41 years in Hulunbuir Sandy Land. Using dendrochronological methods and empirical biomass equations, we estimated biomass, carbon density, and net vegetation carbon sequestration rate (CSR) of Pinus sylvestris var.mongolicaplantation in the past 41 years. Further, we analyzed the relationship between CSR and climatic factors, including monthly air temperature, humidity and precipitation. The results showed that carbon density increased with increasing stand age, with 2.58 t·hm^-2 in 1977 to 87.97 t·hm^-2 in 2017. The interannual variation of CSR showed a trend of increasing first and then decreasing. The average CSR was 2.13 t·hm^-2·a^-1, within a range of 1.37-3.21 t·hm^-2·a^-1. The CSR of Pinus sylvestrisvar. mongolicaplantation was positively correlated with precipitation in the growing season of previous year and current year, and negatively correlated with precipitation in the non-growing season. The CSR was negatively correlated with precipitation in last December and that in current March. The CSR was positively correlated with the average daily air relative humidity from August to September in previous year and current year. The CSR was negatively correlated with monthly average temperature, monthly average minimum temperature, and monthly average maximum temperature. In general, the CSR is affected by temperature and precipitation, with higher sensitivity to temperature. Our results highlight that CSR of Pinus sylvestrisvar.mongolica plantation could decrease in the future due to potential warming in Hulunbuir.