The invention provides a method for pyrolyzing a waste circuit board by using arc plasma. The method comprises the following steps: (1) carrying out coarse crushing on a waste circuit board to be processed, placing the waste circuit board subjected to coarse crushing in an arc plasma arc region; (2) pyrolyzing the waste circuit board in the arc plasma arc region, wherein the plasma working gas is a mixed gas composed of nitrogen and hydrogen; (3) condensing and collecting pyrolytic oil, feeding the pyrolytic oil into a tail gas collection system; and (4) separating pyrolytic scraps to recover metals. The invention further provides a corresponding arc plasma device. The three-phase alternative current arc plasma designed in the invention has the advantages of good continuity, high energy, low cost and convenience for operation and maintenance are convenient, and is beneficial to obtaining the fuel with high heat recycling value, improving the separation recycling efficiency of metals and simultaneously ensuring no secondary pollution when being used for pyrolyzing the waste circuit board.