Abstract: Using real-time upper-air and surface observations from Micaps and radar based data, the environmental condition and echo structure of supercell storms in 10 severe convective weathers over Yichang, Hubei province from 2004 to 2009 have been analyzed. The results show that hail occurred in shallow wet layer, but severe precipitation occurred in deep wet layer. CAPE revised by ground temperature and dew point before the thunderstorm occurred can be used to judge whether the hail will occur in the afternoon. If the revised CAPE value increases greatly (CAPE≥1 000 J·kg-1), the possibility of hail generating is higher, otherwise the possibility is lower. Vertical wind shear (0-6 km) from moderate to strong grade is favorable to the generation and development of supercells, and the stronger vertical wind shear is, the more easily extreme wind emerges. If the characteristic value and characteristic bottom of height of the supercell storms show a rapid decline, gale of more than 8 levels is likely to come in half an hour. When the greater shear means are with the positive / negative velocity area in the supercell storms, the greater wind power is, and the more obvious wind disaster is. Basic reflectivity factors of the supercell storms in the low-level present such echo characteristics as hook-shaped or protuberance to inflow direction or dense bulk, and strong echoes with morethan 55 dBz is situated in the mid-and upper-level. In the supercell storms, mesocyclones is mostly developed from the head wind zones or shear zones, and as for the vertical airflow structure it shows cyclonic convergence in the low and cyclonic rotation with reinforcement of convergence in the medium. Sometimes the double vortex structure appears with coexisting cyclonic rotation and anticyclonic rotation, and it shows divergence with anticyclone in upper air. D VIL (vertical integrated liquid density) has certain prediction significance for large hail forecasting, when D VIL ≥3.5 g·m-3, the possibility of appearance of large hail with the diameter of more than 2 cm is much higher.