CO_2concentrations in different plant communities(larch, birch, lilac, and grassland) were measured during the growing season in the Heilongjiang Forest Botanical Garden to study diurnal variation, seasonal and annual dynamics and factors that impact CO_2 concentration in different spaces. CO_2 concentration in different communities in green lands had an obvious diurnal variation,chronically decreasing, and temperature influenced the lilac area and the grassland. Seasonally, CO_2 was lowest in the larch green land(344.03 ± 23.03 μmol/mol) and highest in the grassland(360.13 ± 22.43μmol/mol). The overall trend in CO_2 concentration was autumn> spring>summer; temperature is the main factor controlling variation in CO_2 concentrations during the growing season; the CO_2 concentration at the larch, birch, lilac, and grassland types of sites was negatively correlated with land surface temperature and air temperature, and the CO_2 concentration at the larch and birch sites was positively correlated with atmospheric pressure. Without any obvious annual change law, further study and observation are needed. CO_2concentrations in different plant communities (larch, birch, lilac, and grassland) were measured during the growing season in the Heilongjiang Forest Botanical Garden to study diurnal variation, seasonal and annual dynamics and factors that impact CO_2 concentration in different spaces. The populations in green lands had an obvious diurnal variation, chronically decreasing, and temperature influenced the lilac area and the grassland. Seasonally, CO_2 was lowest in the larch green land (344.03 ± 23.03 μmol / mol) and highest in the grassland (360.13 ± 22.43 The overall trend in CO 2 concentration was autumn> spring> summer is temperature> the main factor controlling variation in CO 2 concentrations during the growing season; the CO 2 concentration at the larch, birch, lilac, and grassland types of sites was negatively correlated with land surface temperature and air temperature, and the CO_2 concentration at the larch and birch sites was positively correlated with atmospheric pressure. Without any obvious annual change law, further study and observation are needed.