Choke valve is a main component of Christmas tree and designed to control production output of the oil well, the materials of the body and components of choke valve are completely in conformity with API 6A and NACE MR-0175 Standard Specifications, and it is widely used for onshore and offshore petroleum drilling. The throttle valve is mainly used to adjust the flow and pressure of the manifold system; There are two types of flow control valves: fixed and adjustable. Adjustable throttle valves are divided into needle type, inner cage sleeve type, outer cage sleeve type and orifice plate type according to the structure; According to the operation mode, it can be divided into manual and hydraulic two. The end connection of choke Valve is thread or Flange, connected by non or flange. Choke valve falls into: positive choke valve, needle choke valve, adjustable choke valve, cage choke valve and orifice choke valve, etc.