The invention discloses a PCB copper surface oxidizing agent. The PCB copper surface oxidizing agent is prepared from a component A and a component B. The mass ratio of the component A to the component B is 2:(1-2). The component A is prepared from following raw materials in percent by mass: 30%-50% of hydrogen peroxide, 1%-10% of a copper surface inhibitor, 1%-5% of a surfactant and 35%-68% of deionized water. The component B is prepared from following raw materials in percent by mass: 30%-50% of ammonium hydroxide, 9.5%-19.9% of table salt, 0.1%-0.5% of a smell covering agent and 30%-60% ofdeionized water. A copper surface circuit of a circuit board can be oxidized, a dense oxide complex layer is generated on the copper surface circuit of the circuit board, the oxide complex layer can be removed through simple acid washing, thus, the copper surface oxidizing agent is used for carrying out copper surface oxidization on the circuit board before black poration, micro-ethcing is not needed after black poration, thus, a copper substrate of the circuit board cannot be corroded, and the application range of the black poration process is greatly widened.