Abstract: In cost-effective and compact oscillation-type DC circuit breakers for offshore wind power DC collection systems, the configuration of the vacuum switch contacts plays a pivotal role in determining overall interruption performance. The magnetic field distribution in the contact gap not only governs the control capability over the vacuum arc but also directly influences the post-arc dielectric recovery. To explore this, two representative contact structure models are established, and multiphysics simulation methods are employed to investigate their magnetic field distribution characteristics under DC interruption conditions, with comparative analysis against AC conditions. The results indicate that axial magnetic field contacts exhibit a noticeable reduction in interruption capability under DC conditions, while transverse magnetic field contacts demonstrate greater stability and adaptability. These findings offer theoretical insights and technical support for the development of economical and compact oscillation-type DC circuit breakers in offshore wind DC collection systems.