With the extension of the power networks, the cables are widely laid, increasing the burden on inspection power cable operators. To ensure the safety of workers in the cable wells and improve their work efficiency, a visualized intelligent detection device for cable wells is designed in this paper. The device integrates multiple functions, such as temperature and humidity detection, hazardous gas detection, and portable electronic imaging. It can realize real-time monitoring of the equipment in the cable well by electric power operators on the ground. In addition, the temperature, humidity, and hazardous gas content in the well can be measured simultaneously. The device overcomes the problem of the single function of the traditional detection device. And it solves the problem of difficulty and danger of going down the well in the traditional operation method. The experimental results show that the intelligent detection device has the advantages of reliable operation, high sensitivity, and convenient portability. It has important application value for improving the efficiency of power maintenance operations.