The surface energy imbalance problem has been an important challenge in the study of surface land process since it was found in the late 1980s. By utilizing the observed data in the land surface process experiment carried out over the Loess Plateau region in the middle part of Gansu, the characteristics of climate unclosure and short-term unclosure of the surface energy balance are analyzed and the relationship between surface energy balance unclosure and vertical velocity is studied in the paper. It is found that there is a good correlation between surface energy balance unclosure and vertical velocity. Furthermore, the paper estimates the values of vertical sensible heat advection in the surface layer. After considering the vertical sensible heat advection, characteristics of the surface energy balance condition are analyzed again and there is a significant improvement in the surface energy balance unclosure.This means vertical velocity plays an important role in the surface energy buget and the vertical sensible heat advection has a significant influence on the surface energy balance unclosure over the Loess Plateau region.