The invention discloses a plate type contact system of a conventional circuit breaker. The plate type contact system comprises a moving contact group and a contact support, the moving contact group is formed by the connection of a busbar, a flexible connection, and contact sheets in sequence, the moving contact group is arranged in the contact support, the contact support comprises a spring support body, two sides of the spring support body are respectively provided with a lug, the upper parts of the contact sheets are positioned in U-shaped grooves between the two lugs, the upper parts of the contact sheets are supported in lug holes of the lugs at two sides via an upper supporting shaft, two sides of the spring support body are symmetrically and fixedly provided with baffle pieces, a central rotation shaft penetrates through the central parts of the contact sheets and are supported at the baffle pieces at two sides, a U-shaped contact cover is retained at the front surface of connecting positions of the contact sheets and the flexible connection, and a U-shaped insulation guard board is retained at the backside of the flexible connection. According to the plate type contact system, the structure is simple, the adaptability is high, and the work is reliable.