Abstract: A dataset consisting of 16 quasi-linear convective system (QLCS) cases has been developed in east China(116.01?E-119.52?E, 24.5?N-34.29?N ). Statistical analyses of this dataset reveal that radar reflectivity and radial velocity presented a negative correlativity in the leading edge of QLCSs, and the degree of negative correlation changed regularly with heights. Analyses of a QLCS case in Nanjing on 29 June, 2006 show in detail the existence of the negative correlativity between reflectivity and radial velocity. When the QLCS was perpendicular to the radar radial, the degree of negative correlation was most distinct, because, the observed radial velocity in this circumstance approximately equals to the actual wind speed (i.e. maximum radial velocity), while the reduction in horizontal wind resulted from the vertical motion does not change with different detect directions. In this paper, we deduce that the negative correlativity of reflectivity-velocity is associated with convective intensity, mid-altitude radial convergence and rear-inflow jet. The negative correlativity between reflectivity and radial velocity presented here is hoped to be useful for the structure analysis, identification and prediction of QLCSs.