Abstract: The surface temperature in Northern Hemisphere over the past 0.8 Ma was simulated using an improved 2-D energy balance model, and the simulated 65°N surface temperature was compared with the Antarctic ice core record. The climatic effects of integrated insolation, greenhouse gases and dusts, and feedback process of water vapor were investigated via five sensitivity experiments, respectively. The results suggest that the insolation variability given by the Milankovitch theory can’t fully explain the surface temperature changes of the glacial-interglacial cycles in the Northern Hemisphere in the past 0.8 Ma. The influences of the radiative forcing of greenhouse gases and dust, and water vapor on the climate changes since late Pleistocene were very significant. After considering these factors, the correlation coefficient between simulated 65°N surface temperatures and Antarctic temperatures increased from 0.24 in the first test to 0.60 in the fifth one. Finally, the climate system in the model responded to the above forcings and feedbacks nonlinearly.