The validity of ASCAT sea surface wind data in Shandong coast sea is studied using observations at eight representative stations including buoy stations, island stations and coastal automatic stations from January 2013 to December 2014. Results show that ASCAT wind speed is positively correlated with observed wind speed. While the error of ASCAT wind speed is small, the error of retrieved wind direction is relative larger in Shandong coast sea. The quality of ASCAT wind data in Bohai Sea, Bohai Strait and the northern of Yellow Sea is better than that in the middle of Yellow Sea. Under different wind forces, the wind speed deviation of ASCAT from observation is apparently different. When the observed Beaufort wind force is or over grade 6, ASCAT wind speed is always lower than observation, and as observed wind force below grade 6, ASCAT wind speed is always higher. While the mean error of ASCAT wind speed is smaller under lower wind force, the ASCAT wind direction may has larger error than that under greater wind force. In general, ASCAT wind data has good validity in Shandong coast sea. When the observed Beaufort wind force below grade 6, ASCAT wind speed may has relative smaller error, and ASCAT wind direction is relative less reliable.