Based on the map algebra function in ARC/INFO,precipitation erosivity is estimated by the simplified prediction model of daily precipitation using TRMM 3B42 data acquired between 2000 and 2008. The intra-annual and inter-annual spatiotemporal variations of precipitation erosivity are then analyzed. Results show that precipitation erosivity in the Tibet Autonomous Region shows a decreasing trend from the southeast to the northwest with significant spatial variation. The intra-annual concentration degree of precipitation erosivity shows an increasing trend from the southeast to the northwest. The lower precipitation erosivity is,the greater the concentration degree of precipitation erosivity is. The inter-annual variation of precipitation erosivity shows a decreasing trend from 2000 to 2008.