Aiming at the problems brought by traditional turning method used in the manufacturing of stainless steel trapezoidal internal thread, a new method of stainless steel trapezoidal internal thread formation by cold extrusion based on auxiliary vibration is proposed, which effectually solves the problems such as low surface strength and hardness, limited fatigue life and unguaranteed reliability in extreme environment like high-temperature or high-pressure in traditional turning. The experimental exploration on the proposed method is implemented on the machine of internal thread formation by cold extrusion with auxiliary vibration. Results show that this method achieves percentage of thread up to 93.2%, the surface micro hardness reaches over 300 HV, and the surface roughness of the teeth is Ra0.53 μm. Compared with the traditional turning method, the internal thread manufactured by cold extrusion based on auxiliary vibration has great improvement on tooth-shape and surface quality.