Although satellite precipitation has provided a valuable reference for the precipitation estimation in the sparse region， its uncertainties in the practical application are still challenging. Researchers tried to fuse ground observation and satellite precipitation to evaluate and modify satellite precipitation products for uncertainty reduction. Unfortunately， this paper examined many publications of fusion TRMM precipitation products in mainland China and found a non-negligible directional contradiction between the approaches. The findings will significantly affect the reliability of satellite precipitation in practical applications. It was found that the contradiction has not related to the satellite precipitation products and fusion methods but significantly related to the selection of precipitation observation stations. It was also found that the uncertainty is hard to be reduced only by innovating the fusing methods of TRMM precipitation with ground observation data. Therefore， it is necessary to strengthen the integrity of ground observation and adopt independent practices to verify consistency and reliability.