The purpose of this paper is to propose a novel Mecanum wheel-driven spherical robot, which incorporates an internal driving platform with four Mecanum wheels. The four-wheel driving platform concentrates most of the robot’s mass, generating sufficient eccentric torque to enable the spherical robot's movement. Additionally, the Mecanum wheels ensure omnidirectional movement of the driving platform inside the spherical robot, then guaranteeing omnidirectional rolling of the spherical robot. The overall structure and working principle of the pro-posed spherical robot are introduced firstly. The rollers are redesigned for the application of Mecanum wheels on a spherical surface. A Mecanum wheel suitable for spherical motion is investigated, and a three-dimensional model of the spherical robot with four Mecanum wheels is established. A kinematic model of the Mecanum wheel’s spherical motion is then developed. The movement of a single Mecanum wheel and the overall motion of the spherical robot are analyzed.