Abstarct: Induction motor is the most common AC motor in industrial applications where the rotor current is supplied by electromagnetic induction from the magnetic field of the stator windings. Simple design, stable performance, durable and inexpensive structure, efficiency and low maintenance costs are among basic advantages of induction motors, especially squirrel cage and therefore these motors have a special place in the industry. On the other hand, in some applications of these motors can be mentioned to the military industry and secret equipment and facilities. Leakage of magnetic field in the space around electric motors and tracking this field with sensors and special tools is one of the main methods of detecting hidden equipment. Therefore, access to suitable method for evaluating and estimating the leakage of magnetic fields around the motor and also proper design to reduce the leakage field of the rotor is very important. Finite element methods are one of the most common tools for calculating and analyzing magnetic field in electric machines. However, since these methods are baxsed on division problem space into very small components, field analysis at very long distances from the motor requires problem solving with a large number elements and is faced with the problem of high calculations volume. On the other hand, analytical methods are not accurate enough to model the relatively complex current distribution in the windings of electric machines and they make a lot of mistakes, especially when calculating the field away from the motor. In this dissertation, a new combined method using finite element model and equivalence theorem is used to calculate the magnetic field at very long distances from the motor. This method does not have the calculations time constraint of the finite element method and the problem of high approximation in the analytical method. And can be used for all types of electric motors. Using the proposed method, different components of the magnetic field at distance away from a 1 hp cage rotor induction motor are calculated and the effect of different design parameters on the motor leakage field is investigated. According to studies, stator end windings have the greatest impact on the motor leakage field, therefore a solution to control the field of this part of the motor has been considereed. Using the solutions proposed in this dissertation, the leakage field of the induction motor can be reduced up to ten times.