The invention discloses a power converter and a magnetic flux balance adjusting method used for an electronic control air braking system. The power converter comprises a first main power board, a second main power board, a drive circuit, a control circuit and a switching circuit, wherein the input ends and the output ends of the first main power board and the second main power board are respectively connected with a 110 V power supply and the switching circuit through a locomotive power supply bus and PCB wiring; the main topology of the first main power board uses push-pull forward topology, and a magnetic flux balance problem in a traditional push-pull circuit is solved by additionally setting a magnetic flux balance adjuster; the power converter is applicable to working in various environments, power supply is provided for an ECP braking system, the problems such as magnetic flux imbalance of the push-pull circuit and normal working in complicated environments are solved, and the power converter has good application prospects.