Abstract: The analysis of development and background characteristics of cloud images of a warm-shear squall line in spring of Guiyang area on 19 April,2001 by overlapping conventional sounding observations,GMS-5 satellite infrared and vapor images indicate that,newborn convective cells are mainly meso- scales.After developed,they become banded.The lowest cloud top Black-Body Temperature doesnt reach the lowest of its life when cold cloud（TBB-32℃） is largest.All strong convective weathers take place between when the meso-scale convective systems (MCSs) take form and when cold cloud area is largest.Moreover,severe weather emerges in the area of MCSs with dense TBB contours.It can be found that the spring warm-shear squall line in Guiyang is produced at the interfaces of surface warm and wet air masses and warm and dry analogs,i.e.dry lines.Vapor pictures analyses show that,during early stage of MCS,ridgelines of 850hPa e are parallel to water vapor plumes (WVPs) and the place and time of meeting of dark area and lighter dark area somewhat implies emerging place and time of MCSs.