Brushless permanent magnet surface inset machines are interested in industrial applications due to their high efficiency, power density and robustness. An accurate prediction of airgap magnetic field distribution is necessary in order to calculate electromagnetic torque, back electromotive force and self or mutual inductance more precise. The main contribution of this paper is to develop an exact analytical model for magnetic flux density calculation in surface inset permanent magnet machines considering slotting effects, magnetization orientation and winding layout has been proposed in this paper. The analytical method is based on the resolution of Laplace and Poisson equations as well as Maxwell equation in quasi- Cartesian coordinate by using sub-domain method and hyperbolic functions. The developed method is applied on the performance computation of two prototypes surface inset permanent magnet motors. A radial and a parallel magnetization orientation is considered for each type of motor. The results of these models are validated through FEM method.