In this paper, the disastrous influence to the landing aircraft of low-level wind shear and present study to the low-level wind shear field observation have been explained briefly and the method of retrieving headwind profiles from step wise PPI scans in detail. The data with multi-mode analyzed in this paper are based on short range CDL configured at BCIA (Beijing Capital International Airport) from December 2015 to March 2016. The reliability of algorithms have been proved by wind 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 wind shear events under clear conditions.