The invention relates to a mechanical adjusting type gas inlet and flow equalization system of a ventilation air methane thermal reverse-flow oxidization device. The mechanical adjusting type gas inlet and flow equalization system comprises a reaction chamber, two gas inlet and outlet expansion sections and two gas inlet and outlet cavities with an opening in one end. One set of a first mechanical adjusting mechanism is additionally arranged on an outer wall of the top of each gas inlet and outlet expansion section; and one set of a second mechanical adjusting mechanism is additionally arranged on the side wall of the outer part of each gas inlet and outlet cavity. Each gas inlet and outlet expansion section and each gas inlet and outlet cavity are internally and additionally provided with a fixed slotting flow equalization plate and a sliding slotting flow equalization plate respectively; a rack on the sliding slotting flow equalization plate in each gas inlet and outlet expansion section is in transmission connection with the corresponding first mechanical adjusting mechanism; and a rack on the sliding slotting flow equalization plate in each gas inlet and outlet cavity is in transmission connection with the corresponding second mechanical adjusting mechanism. The mechanical adjusting type gas inlet and flow equalization system has relatively good adaptability on different gas inlet working conditions through flexibly adjusting a mechanical adjusting mechanism under an actual working condition that a gas inlet amount has relatively large fluctuation amount, so that uniform distribution of the gas inlet amount and temperature of the reaction chamber, and the operation reliability and the ventilation air methane oxidization rate of the device are improved.