Abstract: Due to harsh operating environment of photovoltaic DC side arcing cable,it is easy to have safety risks such as heating during actual operation.A new heat monitoring method of photovoltaic DC side arcing cable based on non-contact temperature measurement technology was proposed.Infrared thermal spectrum images of photovoltaic DC arcing cable were collected based on non-contact temperature measurement technology,and original images were de-noised and contrast-enhanced.Founded on relative temperature difference of hot spots in infrared thermal spectrum images after preprocessing,heating condition of the cable was judged to realize heat monitoring of photovoltaic DC arcing cable.Results showed that the error between temperature monitoring data and actual data was only 0.90℃,which verified that the method was feasible and reliable.