Abstract:“Haikui” (No.1211) is an intensified typhoon, but the remarkable differences of its intensity determination were presented by CMA, RSMC Tokyo and JTWC. Cloud image analysis shows that “Haikui” is a severe typhoon with the TBB below -70℃ for a long period in offshore area. Radar data reveals its symmetrical structure, clear eye and enlarged scope obviously before and after its landing. Long time lasting gale is also detected by the coastal observation stations, including automatic stations and inner island stations. The gust with the intensity above 13 grades lasts for 26 hours during the period. The maximum wind speed is 46.9 m·s-1, 39.4 m·s-1 and 36.8 m·s-1 measured respectively at Dongji Station, Dachen Station and Shipu Station. The vertical wind shear difference is 7-8 m·s-1 under the height of 500 m. These ground based observations show that “Haikui” has matched the standard of severe typhoon, and the intensity determination by CMA is reliable accordingly. Therefore, it is concluded that the determination of typhoon grade should depend on not only the Dvorak technique, but also the ground based detection data.