Static mixers, which do not require external energy sources, are characterized by their compact design and ease of integration into systems, making them highly valued in the food processing industry. The introduction of vortices can significantly enhance the mixing efficiency of mixers, leading to improved reaction rates and overall effectiveness. Currently, most vortex static mixers achieve high-efficiency mixing by generating vortices through their internal structures, which must withstand the impact of flow and thus carry a risk of damage. Vortex tubes, characterized by their simple structure and strong vortex properties, have yet to be studied for their effectiveness in mixing. Based on this, this work investigates a vortex static mixer, employs numerical simulation methods to study its flow and mixing characteristics, focusing on the effects of inlet velocity and structural parameters such as the chamber aspect ratio (D/H) and the axial diameter ratio (D/Da). The results show that the internal flow is primarily dominated by vortices, accompanied by significant secondary flows, including secondary vortex circulation flow zone, shortcut flow zone, and eccentric vortex zone. Increasing the inlet velocity enhances the internal vortex flow and weakens the secondary flow, significantly reduces the intensity of separation at the outlet. When the inlet velocity reaches 0.223 m/s, complete mixing can be achieved at the chamber outlet. Reducing D/H or increasing D/Da can enhance the internal vortex. The mixing performance improves as the D/H decreases. Specifically, when the D/H is reduced from 6 to 4, the intensity of separation at vortex chamber outlet decreases from 4.03×10-3 to 5.23×10-4.