The paper develops a safety early-warning system for live working based on human physical signs. Four parameters are selected for real-time monitoring

including skin temperature

heart rate

inner environment temperature and inner environment humidity. The index and judgment logic of safety early warning are established and the functional test and high voltage electric field test of the system are carried out. The test results show that the system can realize the real-time monitoring and evaluation of the health status of the operators

and has the ability to resist the strong electric field interference of 500 kV and below

which meets the requirements of the working environment for the actual production of live working.