The data of single station lightning detection and ranging system and 713 radar echoes achieved from 4 cold vortex hailstorm events from 1996 to 1997 are analyzed. The results show that the number of times of lightning have a brewing and leaping procedure before the hail begins to drop 5 minutes,it reaches the maximum when the hail begins to drop and after the hail dropping it descends slowly. The distribution of cloud discharge and total lightning frequency corresponds with this phenomenon better. Comparing the ground area hitted by lightnings and the ground place of hails dropping on,it is found that the area coincides with the place well. Put the lightnings' place and the intensity data on top of the radar echoes picture,it is found that the place where lightnings appear frequently is just the place where the radar echoes are strong.