The invention discloses a mold punching on-line detecting device. The mold punching on-line detecting device comprises a punching mold; the punching mold comprises a female mold seat, a male mold seat, a discharging plate, a male mold, a female mold fixing plate, a female mold, a female mold material falling cavity, a female mold cavity and a female mold seat material falling cavity; and the device further comprises a material supply sensor and an on-line detection apparatus. By adopting the mold punching on-line detecting device, strips are accurately limited and positioned, equipment abnormity is detected in time, equipment alarm emergency stop is achieved, fast, stable and intermittent punching can be achieved, the production efficiency is improved, and the product quality is guaranteed.