An analytical method of calculating the normal and tangential forces in linear synchronous motor with air-core and Halbach permanent magnets is developed. First, the analytical solution to the normal and tangential forces of the rotary motor with the same structure is deduced. Then, the proposed method is extended to linear motor, and the analytical method of computing the normal and tangential forces in linear synchronous motor with air-core and Halbach permanent magnets is obtained. Finally, the effectiveness of the proposed analytical method is validated by Ansoft Maxwell, which is a famous finite element analytical software. The proposed solution provides an important tool for structure design and performance analysis of linear synchronous motor with air-core and Halbach permanent magnets.