By using soil temperature data from ANDUO, TTH and NODA station along the Qinghai-Tibet railway, the soil heat fluxes at 3 different depths in these 3 stat ions from September 1997 to August 1998 are calculated by use of integral method. Based on the multi-time scale analysis method, the time series of the soil heat fluxes is analyzed, and some important characters on the variation of soil he at fluxes against time and depth on different time scales are concluded.