The invention relates to the technical field of anti-misoperation of the ring network cabinet, and particularly relates to a portable anti-misoperation warning device comprising a box body, a flashingbuzzer, a warning indicating lamp, a power switch, an infrared sensor module and a lithium battery pack. The box body is fixed on a switch cabinet operation panel of a ring main unit. The flashing buzzer, the warning indicating lamp, the power switch, the infrared sensor module and the lithium battery pack are installed inside or on the box body. The normally-open point of the power switch and the normally-open output point of the infrared sensor module are connected in series with the flashing buzzer and then connected to the positive and negative ends of the lithium battery pack. The warning indicating lamp is connected in parallel on the two ends of the flashing buzzer. When the warning device is turned on and switched to the warning state, the warning device emits a sound-light alarmsignal to prompt the operator and the supervisor of correcting violations of regulations in time when someone approaches a switch operation mechanism.