Abstract: Based on the real case of a frontal precipitation process affecting South China,27 controlled numerical experiments was made,aiming at impacts of hydrostatic and nonhydrostatic effects,different driving model,different initial/boundary conditions,different renew periods of boundary values,as well as different initial dates,on model predictions. And some technically and practically valuable regulations and features about the impact of initial/boundary conditions on mesoscale numerical weather prediction (NWP) model were analyzed and discussed in detail. It is considered that the overall tendencies of mesoscale NWP model are governed by its driving model,with the initial conditions showing remarkable impacts on mesoscale models only within about the first 10 hours of predictions,while predictions longer than 10 hours are mainly dominated by lateral boundary conditions,which affect inner area of mesoscale predictions through propagation and movement of weather signals (waves) of different time scales. In addition,some initial values of external model parameters such as soil water content may affect predictions of more longer time,while fast signals may be filtered away and only the information with time scale of equal to or larger than 4 times of the updated period of boundary values may be introduced,through lateral boundaries,with mesoscale models,etc. Some results may be taken as important guidance on mesoscale model and its data assimilation developments of the future.