Abstract: Effects of geothermal flux on soil temperature and land surface energy budget are discussed by introducing a soil heat flux into an off-line land surf acemodel(NCAR LSM) and integrating for 2 years.Remarkable increase in soil temperature at deepest level is detected given a geothermal flux of 5 W/m2.Additional heat flux from soil into land surface exceeds 1W/m2 after integrated for 3 months.The flux keeps in-creasing until reaches 5 W/m2.Amaximum anomaly of 0.5K is found in ground temperature.Correspondingly,there are positive anomalies of around 1 W/m2 in surface sensible,latent and outgoing long-wave radiation fluxes.Increase in ground temperature can be even greater than 1 K given an enlarged soil thermal conductivity by one order of mag nitude to accelerate the heat transfer process through soil layers.In this case,surface long-wave radiation flux is then enhanced not ably by 3 W/m2,which is larger than the global radiative effects of sulfate aerosol.The results imply that soil thermal anomaly on a certain scale should not be ignored to land surface energy balance and short-term climate change.Meanw hile,some related studies,such as dat a analyses,improvement of land surface model and land-at mosphere coupled model are also in greatneed for better under-standing this issue.