The band echo of the gust front of a severe hail storm system is found out during radardetection of the hail storm. The properties )structure and causes of the band echo of the gustfront are discussed. The reactions of the band echo of the gust front on the hail storm systemare analyzed. The band echo of the gust front is different from that of the gust in a classicalmodel. The self-trigger mechanism for continuation and conveyance of the hail storm systemis given. Application of the band echo of the gust front to nowcasting is considered tentatively.