With the continuous increase in the drilling depth of oil and gas wells, drill pipes are subjected to greater axial forces and torques. As a relatively weak structural component, drill pipe threads require mechanical strength analysis and structural optimization. Finite element analysis (FEA) models was established for the mechanical behavior and crack propagation of standard API(American Petroleum Institute) threaded joints and structurally optimized non-standard new threaded joints under multiple working conditions. The FEA results show that the non-standard new joint has higher mechanical strength, it is easier and faster to make up, and features three non-working threads, which reduce the stiffness at the large end of the threaded joint and alleviate stress concentration problems. Specifically, the torsional strength of the non-standard joint is 23.86% higher than that of the standard joint, the cross-sectional stiffness at the thread root is increased, and the crack propagation lengths at the third internal and external shoulder threads are significantly reduced. This effectively suppresses crack propagation, with fracture wall thickness reduced by more than 40%. During the drilling process of the 10 000 meter ultra deep Chuanke 1 well developed in Sichuan, the non-standard new type of threaded joint will be used. The research methods and results in this article provide a theoretical basis for the design of non-standard new drill pipe threads in ultra deep wells.