Forest is the leading sink of carbon on the earth, while the forest resources of Heilongjiang Province take an important position in China. Based on the national forest inventory data from 1973 to 2003, the carbon storage of forests in Heilongjiang Province was estimated by the linear relationship between stand biomass and volume. The results showed that the total carbon storage of forests in 1973-1976, 1977-1981, 1985-1988, 1989-1993, 1994-1998 and 1999-2003 was 7.916 x 10(8), 5.413 x 10(8), 5.661 x 10(8), 5.880 x 10(8), 6.216 x 10(8) and 6.011 x 10(8) t, respectively, with an increasing trend since 1977, indicating that the forests in this Province played a role as a sink of atmospheric carbon dioxide, and this functioning was strengthened during the last 20 years. If the current forest is managed well, it would become a huge potential carbon sink in the future.