Aiming at the vibration bounce problem caused by the collision and contact of the static and dynamic contacts of the electrical switching device during the closing process， a two-degree-of-freedom vibration equation of the contact system is established and solved based on the comprehensive consideration of the nonlinear electromagnetic force and the collision contact force，. For the first time through a high-speed photography experiment， the law of contact bounce and deflection is revealed. The results show that the theoretical and experimental results are highly consistent. The iron core collides before the contact is separated after the collision， which further aggravates the contact bounce. The second bounce of the iron core does not affect the spring of the contact. After the first collision， the movement track of the moving contact produces the first deflection， and after the second collision， the deflection displacement and angle are opposite and less than the second. The results provide a theoretical basis for further control and reduction of contact bounce.