To study the effect of special threaded joints on tubing in complex working conditions,Abaqus finite element software was used to build the finite element model of the threaded joint.The initial threading state was simulated under a certain radial and axial interference,and the overall structural integrity and sealing performance of the special threads of the tubing were analyzed under different axial load,internal pressure and temperature.An overall sealing performance index,partial sealing performance index,and comprehensive safety performance evaluation method were established.The result shows that the Mises stress and contact pressure of special threaded joints show a concave distribution trend under different working conditions.The position of the first and last buckle undercut grooves is the weak part where the stress is relatively concentrated.The increase of temperature difference leads to a significant increase in the stress level of thermal expansion and contraction deformation the joint structure.The increase of internal pressure and axial load can improve the overall sealing performance,but there are differences in the partial sealing performance of the shoulder.The use of threaded grease in the joint improves the overall and partial sealing and safety performance of the threaded joint.The higher the internal pressure and the higher the temperature,the lower the safety of the joint.The overall safety performance of the thread under tensile load conditions is improved,but the separation of the local shoulder joints reduces the safety.The overall safety of the thread under compressive load is increased,but duo to the influence of the thread structure and compression resistance,the safety performance will decrease when it exceeds a certain load.