Abstract: The high pressure well is easily blocked by hydrate and bring major potential safety hazard. Aiming at this productive problem, downhole choke engineering research was developed. According to the downhole choke mechanism and based on the gas flow rule in well bore and strata radial heat transission, the well bore pressure and yield temperature forecast mathematical model was built, and solved it by LongGekuta method. Adopted compositional model and constant entropy enthalpy change to forecast choke heat drop. According to the rates, hydrate spanning condition, tub pressure and temperature distribution, and processing parameters were ascertained. Used the downhole choke design model to design the processing parameter and do field test in Chuanxiao 452 well, and got good effect.