A temperature detection system of a power cable is provided to prevent a fire caused by overheating and an electric leakage by exactly checking the abnormal state of the power cable through a temperature sensor and an alarm. In a temperature detection system of a power cable, a thermal contact alarm is composed of a sensor communication control unit(11) controlling data communication between a temperature sensor(10) and the alarm; an operating unit(40) setting a temperature range or temperature rise rate that is a reference for generating an alarm by a user and inputting or deleting ID(Identification) addresses of each temperature sensor; a data storing unit(30) storing a set value of a user and the ID addresses of each temperature sensor; a display unit(50) displaying the set value inputted from the operating unit and a temperature value detected by the temperature sensor, on a display part; an alarm unit(70) generating an alarm if the detected temperature is over a set temperature range or the temperature rise rate exceeds the pre-set temperature rise rate; a CPU(20) controlling each unit; and a power supply unit(80) supplying power to the alarm.