Abstract: A design of Φ177.80 mm×8.05 mm K55 thread type for the thermal recovery well service is proposed.The material evaluation of the thread type is conducted as per ISO/PAS 12835, and the FE theoretic analysis under the material model and the structural model is made.The characteristic point of stress and strain curves at different temperatures as obtained via the material property analysis can be input as data into the FE software.The FE method is used to evaluate the effects by the poorest working conditions of different structural tolerances and the material property change on the sealing performance under the optimal make-up and temperature circulation conditions, and the requirement for the torque for the last make-up.Finally the structural integrity of the thread under the effect by the temperature load circulation is analyzed.It is revealed via the analysis of the ultimate loading stress that no slipping, necking and buckling of the thread are found under the condition of the entire temperature loading circulation.