The invention provides a temperature monitoring device and a high-voltage insulation sleeve system. The temperature monitoring device comprises a containing pipeline, a sensor and a temperature processing device, wherein the containing pipeline is used for being connected with the inner wall of a conductive rod of a high-voltage insulation sleeve; the sensor is arranged in the containing pipelineand used for detecting the temperature of the inner wall of the conductive rod; the temperature processing device is arranged on the outer portion of the high-voltage insulation sleeve and connected with the sensor, and the temperature processing device is used for receiving and processing temperature detected by the sensor and displaying the temperature. In the temperature monitoring device, thetemperature of the inner wall of the conductive rod is detected through the sensor, the temperature processing device processes and display the temperature, and the temperature in the high-voltage insulation sleeve can be directly measured; the sensor is arranged in the conductive rod through the containing pipeline 1, so that the sensor is not affected by the outside environment, the measurementaccuracy is improved, the measurement error is greatly reduced, comprehensive monitoring of the whole running temperature of the high-voltage insulation sleeve is facilitated, and therefore, it is ensured that the high-voltage insulation sleeve stably and reliably runs.