The　images　of　arc　motion　of　the　electrical　apparatus　during　breaking　process　are　taken　by　the　test　device　based　on　high-speed　camera　in　this　paper.　By　means　of　a　series　of　processing　methods　such　as　median　filtering,　Gaussian　filtering,　grayscale　transformation　and　binary　conversion,　the　arc　images　are　processed　and　the　total　pixel　values　of　arc　images　are　calculated　to　complete　the　numerical　representation　of　the　arc　morphology.　The　relationship　between　the　arc　pixel　area　and　time　during　the　whole　process　from　arc　ignition　to　extinction　is　studied.　It　can　provide　the　basis　for　the　study　of　arc　motion　discipline.