The invention relates to a deep soil thermal parameter monitoring sensor and a detection method. The deep soil thermal parameter monitoring sensor mainly comprises a DC voltage-stabilizing voltage source, an insulated heating wire, a spherical probe, a temperature measurement module, a monitoring device, a balancing resistor, and a data collection unit. The DC voltage-stabilizing voltage source is used for supplying power to a heating circuit. The insulated heating wire is used for heating the probe. The probe is in the form of a hollow spherical shell made of copper-zinc alloy, and is embedded into the soil to measure the thermal parameters of the soil based on the heat transfer condition of the surrounding soil. The temperature measurement module comprises a thermal resistor as a temperature sensor and the thermal resistor is arranged on the inner surface of the spherical shell of the probe. The thermal resistor is used for measuring the temperature change on the surface of the probe. The monitoring device is composed of a resistance voltage divider and a sampling resistor and is used for monitoring the voltage and the current at the two ends of the insulated heating wire. The balancing resistor is used for stabilizing the output voltage and the temperature change before the measurement. The data collection unit is used for collecting the temperature on the surface of the probe, the voltage and the current at the two ends of the insulated heating wire. The deep soil thermal parameter monitoring sensor is convenient in measurement, rapid and portable. The deep soil thermal parameter monitoring sensor can be directly buried deep underground to monitor the thermal parameters of the soil surrounding a cable in real time.