By using the T106 data and filter method,the mesoscale precipitation systems have been found,and the characters and variations of some meteorological elements also have been analyzed.It is found that by analying and tracing the mesoscale systems,the rainstorm forecasting could be more accurate.The strong convergence of moisture corresponds to the rainstorm well in time and position.We must pay attention to the southern warm thermal advection as well as the northern cold thermal advection in the cold front shear type rainstorm process.