The invention discloses a machine for automatically measuring the length of a braid belt. The machine comprises a touch screen, a control switch, a belt feeding roller, a belt discharging roller, an electron beam reflection control switch, a belt falling cylinder, an operation platform, an iron stand, an infrared induction switch, a servo motor, a limiting switch, an encoder, a roller and an electric control box; a control switch is arranged below the touch screen and is fixed on the operation platform; the belt feeding roller is arranged in the iron stand; the infrared induction switch is installed below the belt feeding roller, the electron beam reflection control switch is arranged in the belt falling cylinder, the limiting switch is installed above the belt falling cylinder, the rolleris arranged on one side of the belt falling cylinder, the encoder is arranged on the other side of the belt falling cylinder, and the belt discharging roller is arranged on the other side of the encoder. Mechanical equipment is adopted for automatically metering the number of product lengths, the speed is high, the accuracy is high, and the problems that metering is conducted on equipment in a packaging mode, tension is uneven, and the number is different due to manual operation techniques are solved.