Wirelessly actuated microrobots own promising potential in next-generation invasive therapies, due to their tiny structures and volumes. However, it is still a huge challenge to enable more functionalities with such limited structures. In this paper, we report a novel magnetically actuated hollow continuum microrobot, which reserves more available space for potential component integration. Silicone serves as the mainframe structure, enabling soft deformation. Several small magnets function as the actuation part, providing powerful output forces. Some non-magnet parts are removed to provide a soft cavity, that facilitates cargo delivery and in vivo sampling with untethered actuation. Theoretical study and experimental testing are carried out to demonstrate the effectiveness of the reported design. The soft structure offers a new strategy to achieve multi-modal motion. The proposed design scheme provides a promising solution to better improve the mechanical structure of microrobots, advancing their further applications for medical use in the future.