The invention discloses an operation state monitoring method and system based on temperature measurement high voltage cables. The method comprises steps that when the temperature measurement high voltage cables are in normal operation, core temperature values and core current values of multiple sets of temperature measurement high voltage cables are collected, the corresponding relationship is further established, an expert database is formed, and the corresponding relationship is stored in a standard database; a current difference value of a core current value detected under one certain core temperature in real time and a core current value of the standard database is calculated; the current difference value is compared with a preset current difference threshold, an alarm state is controlled according to the comparison result, and an operation state of the temperature measurement high voltage cables is monitored according to the alarm state. The invention further provides an operation state monitoring system based on the temperature measurement high voltage cables. The method is advantaged in that the alarm state is controlled according to the comparison result of the current difference value and the current difference threshold, the operation state of the temperature measurement high voltage cables can be effectively monitored through checking the alarm state, users can be timely prompted to maintain the temperature measurement high voltage cables, and safe operation of cable lines is guaranteed.