The invention provides a vibrating rod gradient detection and quality monitoring method and system. A vibrating rod is used for vibrating concrete; when an operator inserts the vibrating rod into the concrete and does not keep vertical to the ground or limit the gradient, the concrete strength quality is damaged. In a shell, an angle sensor induction part is fixed on a non-rotation member at the lower part of an eccentric gear or a planet gear; an electric signal is led out of the shell and is externally connected with a single chip microcomputer input port of a control board; and the non-rotation member is a lower bearing block or a circular plate which is fixed to the inner surface of the bottom end of the shell. A normal work and gradient control loop comprises a start-stop button, a self-lock relay, a single chip microcomputer and an execution circuit; and a power line is connected with a self-lock contactor. During the normal vibrating process, the start-stop button is operated; and during the gradient monitoring process, the angle sensor, the single chip microcomputer and the execution circuit control a motor power supply to shut down and to stop rotating. The single chip microcomputer is provided with a gradient detecting digital recorder or is added with a display. The concrete construction quality is effectively ensured; the vibrating rod gradient is monitored, recorded and eliminated in real time; and a detecting and monitoring loop is reliable and low in cost.