The invention provides a method and system for inverting the ground PM 2.5 through combination of geostatistical interpolation and satellite remote sensing. The method comprises: based on a space-time kriging interpolation model and a constructed space-time variogram model, obtaining a first concentration value of the ground PM 2.5 of a to-be-inverted region; based on a constructed satellite AOD inversion model, obtaining a second concentration value of the ground PM 2.5 of the to-be-inverted region; and fusing the first and second concentration values to estimate a final concentration value of the ground PM 2.5 of the to-be-inverted region. A weight relationship is established according to the root-mean-square error of the first and second concentration values, and the first and second concentration values are fused according to the weight relationship to estimate the final concentration value of the ground PM 2.5 of the to-be-inverted region. According to the method and system, the estimation accuracy of PM 2.5 is improved in a situation that ground monitoring stations are less, and the defect that PM 2.5 cannot be estimated at the place where AOD data is lost is overcome.