Two methods for retrieving the average divergence and radial divergence are introduced by means of the Doppler radar radial velocity data. Their application in rainstorm tracking and heavy rainfall forecasting is discussed, as an example, by a rainstorm process on 11 and 12 July 2004. The results indicate: (1) The average divergence field can be used as the background of rainstorm tracking and heavy rainfall forecasting. Before precipitation, there exists convergence at low levels averagely. If the convergence strengthens or maintains, precipitation will increase in the whole region. While if the height of the convergence lifts at middle levels and maintains, precipitation will be the strongest. If the convergence weakens or begins to become divergent at low levels, regional precipitation will gradually end. (2) According to the distribution of radial divergence, the area of heavy rainfall can be forecasted two hours ahead: the area of heavy rainfall will be within the rear weak convergence zone of the largest radial convergence area; the stronger the intensity weak convergence zone is, the greater the rain intensity is. Therefore, by means of the comprehensive analysis of average and radial divergence changes along with time, the development and evolution of precipitation can be tracked and forecasted, especially, the area of heavy rainfall can be located roughly.