Hsu works in the area of remote sensing of precipitation and hydrologic system modeling. He is specifically interested in the development artificial intelligent and remote sensing techniques in the classification and decision making of hydrologic systems.

Hsu's current research activities are in the development of PERSIANN system to accurately determine the spatial and temporal distribution of precipitation using information from satellite and in situ (radar and gauge) observations. The classification of precipitation type (rain or snow) during the cold seasons and uncertainty analysis of model estimates are being investigated. He is also involved in the watershed hydrologic modeling using remote sensing data.

He is currently doing research for the Center for Hydrology & Remote Sensing (CHRS), HSSOE Department of Civil & Environmental Engineering.