Abstract: A position indicator for isolation switches based on QR code is proposed in this paper, which can replace existing isolation switch position indicators by integrating commonly used signs and QR codes of substation equipment. The opening and closing positions of the isolation switch can be determined based on the color and text in QR code. Moreover, the information of the opening and closing positions of the isolation switch reflected by the QR code can be write into the logic of microcomputer error prevention system. The microcomputer error prevention device acts only when the scanning information of the isolation switch is for the opening or closing positions. The QR code plays the role of opening and closing position indication and anti-misoperation.