Abstract: As the development of coiled tubing(CT) technology and drilling technology, coiled tubing drilling (CTD)was concerned extensively and developed significantly in early 90’s. At present, CTD has been applied in side tracked horizontal drilling, multilateral drilling and under balanced drilling to incease ROP,drilling efficiency and safety,and reduce laboring and drilling cost. CT units has been introduced in China in many years, however, mostly applied in workover operation other than even in drilling test. This paper describes CTD’s surface equipment and bottom hole drilling assembly,their features and operation as well as future trend. Finally,several recommendations for its development in China are proposed.