The television monitoring technology becomes an important method in the automation of the substation and electrical network, which raises a higher level to the switch frequency monitoring picture processing algorithm research. Based on the analysis of the classical edge detectable operator, and in view of the high voltage switch characteristic which is in the transmission line, one edge detectable algorithm is proposed.This algorithm considers initiatue recognition, and just paritialy process the images, this paper which reduces a huge processing, and raises processing speed. The GW17-550D type high voltage switch of close situation and GW22-12 of open situation are adopted classic edge detectable operator and the proposed detectable algorithm respectively to simulate.The simulation results show that the new algorithm is more satisfied.