In this paper, the disastrous influence to the landing aircraft of low-level w ind shear and present study to the low-level w ind shear field observation have been explained briefly and the method of retrieving headw ind profiles from step w ise PPI scans in detail. The data w ith multi-mode analyzed in this paper are based on short range CDL configured at BCIA ( Beijing Capital International Airport) from December 2015 to M arch 2016. The reliability of algorithms have been proved by w ind shear reports from the crew and the airport terminal control office. CDL has been proved to be an effective tool to capture the low-level w ind shear events under clear conditions.