Plate positioning mechanism and punching machine thereof

The utility model discloses a plate positioning mechanism and a punching machine thereof, which comprise a positioning assembly, the positioning assembly comprises a lower clamping plate, an upper clamping plate is arranged above the lower clamping plate, a mounting plate and a light emitting assembly are arranged above the upper clamping plate, the light emitting assembly comprises a mounting sleeve, a laser pen and a refraction assembly are arranged in the mounting sleeve, and the refraction assembly comprises a strip-shaped triangular block. Reflecting glass is embedded in the top of the strip-shaped triangular block. The arrangement mode that the light emitting assembly, the refraction assembly and the punching machine are matched is utilized, a colored light beam parallel to a plate can be formed on the upper surface of the plate to be punched through the matching of the light emitting assembly and the refraction assembly, a reference object is provided for operators, the plate deflection phenomenon is r