The present invention relates to a water-based pore sealing agent enhancing PCB coating anti-oxidation and anti-corrosion properties, consisting of, by weight, 4-12 parts of a corrosion inhibitor, 15-25 parts of a mixed surfactants system, 10-20 parts of an ion chelating agent, 6-15 parts of a pH regulator, 20-40 parts of a builder, and the rest being purified water. When used to perform pore sealing on a PCB, the water-based pore sealing agent is diluted with purified water first to be diluted 10-100 times, preferably, 100/8-100/3 times. The pH value is 7-11, and is preferably 7.5-9.5. The surface tension is 18-28 dyn/cm. The pore sealing treatment uses a immersion process, and preferably ultrasonic waves are added at the same time to assist in cleaning the pores. For the pore sealing treatment, the temperature is 20-60° C., and the time is 60-150 seconds. After pore sealing, the temperature for drying the coated piece is 80-150° C., and the time is 60-120 seconds. The PCB treated with the water-based pore sealing agent of the present invention undergoes the neutral salt spray test, the nitric acid vapor test, the mixed gas test, and the sulfur dioxide and bonding tensile strength test, and the results have indicated that the anti-oxidation and anti-corrosion properties of the coating thereof are significantly enhanced.