The low temporal resolution of TRMM data could cause systematic errors in the rainfall erosivity calculation within the specified time period. For this reason,we propose a method of calibration in order to reduce the errors in this paper. Firstly, a relationship table of rainfall erosivity at different events and duration with typical rainfall process is established with historical rainfall data or numerical simulation; then, the corresponding difference is calculated from the above table based on the precipitation and duration of each rainfall in the study area; afterwards, the adjusted value of rainfall erosivity in each rainfall is calculated by multiplying the figure found in the pervious step by the original value of rainfall erosivity correspondingly; finally, the calibrated value of daily, monthly or yearly rainfall erosivity is obtained by adding daily, monthly or yearly adjusted value of rainfall erosivity correspondingly. To verify the effectiveness of this calibration method, the typical rainfall process in the study area, the upriver regions of Jiyun River, was simulated within Matlab 2010b to obtain therelationship table, and then the rainfall erosivity in the study area was calculated using TRMM 3B42 data in 2008 with the spatial resolution of 0.25°×0.25°and the time resolution of 3 h. The calculation was conducted in the ENVI - IDL Language program and calibrated by the relationship table. The results showed that: the rainfall erosivity in the upriver of Jiyun River ranged from 900 to 2 900 MJ·mm/ (hm²·h) with the highest values in central area, followed by southern and northern parts, which was consistent with the local average annual values and distribution of rainfall erosivity. The results confirm that this method can effectively improve the precision of TRMM data爷s application. Due to the limitation of spatial resolution of TRMM data, this calibration method is only applied in the rainfall erosivity calculation at large and middle scales. In order to improve the precision of this calibration method, the typical rainfall process, rain type design and distribution of rainfall duration should be detailed.