Based on the Doppler radar data, a technique is described with the cross correlation method to heavy rainfall nowcast. Similar patterns of radar echoes are detected by comparing tracking areas in consecutive scans. The best fit between the tracking area is found by optimizing the correlation coefficient. The displacement vector corresponding with the max correlation coefficient is used to extrapolation rainstorm for periods between～quarter and one hour. The technique is validated by the use of observational data of “China Heavy Rain Experiment and Study CHeRES”. It is showed that displacement directory of rainstorm nowcasted by cross correlation is consistent with that of radar observation, the forecast veracity is decreasing with forecast lead time.