High-voltage Disconnector are one of the most numerous types of equipment in substations. High-voltage Disconnector are mainly shut down for inspection and maintenance during the spring and autumn inspection periods. Generally, circuit resistance tests and feeler gauge measurements are used to evaluate the quality of switchgear maintenance. However, the relevant test results are relatively one-sided. There is a hidden danger of heating of the contact fingers shortly after the knife switch is overhauled and put into operation. The existing detection scheme cannot reflect the actual operating status of the switchgear. Based on the mechanical clamping force visualization structure, this paper designs an online monitoring device that can monitor key indicators such as the contact finger pressure value and temperature in real time. The RFID-type passive wireless sensing scheme is adopted to realize the real-time transmission of the monitoring signal value. The threshold judgment method, the change trend comparison method and the neural network threshold method are integrated to perform real-time calibration and analysis of the contact finger pressure and temperature, and to provide real-time warning of possible faults of the switchgear. Experiments show that the developed online monitoring system for the operating status of High-voltage Disconnector can provide advance fault warning of defects such as insufficient clamping degree of the knife switch and heating, which is of great significance to assist the digital transformation of power grid operation and maintenance and ensure safety of the grid.