The invention discloses a valve opening sensor of a canning vehicle, comprising a sensing probe and an inductor. The valve opening sensor is structurally characterized in that the sensing probe is in the shape of a circular ring, fixedly connected with a rotatable valve rod and arranged concentric with the valve rod, and the set central angle position of the sensing probe is provided with a signal generator; the inductor is fixed on a valve seat and provided with a signal receiver; a valve rod angle probe is formed by the signal receiver arranged on the inductor and the signal generator arranged on the sensing probe, and an output signal of the valve rod angle probe passes through a singlechip processing circuit and then is accessed into a signal emitting circuit. The invention detects multiple opening angles, has oil rub resistance and interference resistance without any structural change in concrete implementation for the traditional valve, easy installation and low cost and can detect in real time and effectively solve the problem that the secret discharge of transportation goods of the canning vehicle during transportation can not be monitored in real time.