This paper firstly presented a mathematical model of the radial stiffness of a wire race ball bearing in a certain type of three-axis aircraft simulating rotary table. The Stribeck theory was used to determine the radial load distribution of the bearing. By treating the contact between balls and wires as equivalent compression springs, the relationships of these springs in series and parallel can be obtained to solve the total radial stiffness. Experiments verified the theoretical results of the radial stiffness. This work provides an effective support for further studying the complex contact dynamics of the wire race ball bearing in the future.