Abstract: Described here in the essay are the research and development process of the special drill pipe for deep slim hole sidetracking drilling service,detailing such aspects as the design process,the key manufacturing technology and application effectiveness. The said special drill pipe with stable performance and long service span is developed by means of proper structure design,the tube body upsetting and heat treatment processes. The actual operation result shows that compared with the API S135 drill pipe,during the slim hole sidetracking drilling process,the annular space in the joint position of the newly-developed special drill pipe for the deep slim hole sidetracking service can be increased up to 10 mm,meanwhile the stress concentration is effectively dispersed so as to get the drilling efficiency and operation safety improved. The special drill pipe for deep slim hole sidetracking drilling as developed provides an effective solution for window sidetracking drilling over 6 000 m,being capable of good social benefit.