Abstract: Based on documents from Doppler radar,Ground-Based Microwave Radiometer and Laser Disdrometer,we analyze a hailstorm process on April 13th,2017,Yibin,and discuss the applications of the new detection data in the hail monitoring and warning.(1) The step trough is an important circulation pattern in hailstorm process,and the short wave north trough triggers the explosive release of instability energy.The deep of vertical section exists between 0~6km,and attitude of 0℃ exists in about 3.5km.(2) The radar echo character of this hailstorm process is:the appearance of bow's multi-cell convective storm,BEWR and suspension echo exists in vertical structures,VIL jumped evidently by four times,the density of VIL is greater than 4 g·m^-3.(3) Before the hailstorm,the relative humidity manifests a 3-layer structure of vertical division,the K index is 40℃;in the process,the relative humidity manifests a 2-layer structure of vertical division,the K index fluctuates obviously;Total atmospheric water vapor content and total amount of atmospheric liquid water increases dramatically and hailstorm happens in the crest of wave.(4) The hailstorm interval observed by Laser Disdrometer is 20:56~21:19,the hail maximum diameter is 8.5mm;the diameter of precipitation particle is small,most of which are only 0.2~1mm,raindrop size distribution manifests a bimodal distribution,raindrop size widens and hailstorm increases on double front.