A numerical analysis was conducted on the flow and heat transfer of the cell plate structure of a certain gas air plate heat exchanger. The surface of the plate is composed of two types of cells, 6mm high and 3.5mm high, arranged and combined according to a certain pattern, with a flow channel width of 12mm. Simulation calculations were conducted using high-temperature flue gas and air as heat transfer media, and it was analyzed that the heat transfer performance of 6mm pits and convex cells was superior to that of 3.5mm pits and convex cells. Therefore, an improved design was made for the heat transfer plate, replacing all 3.5mm pits and convex cells with 6mm pits and convex cells. The number of support points was increased from 21 to 94, and three plate design schemes were proposed for the longitudinal, herringbone, and transverse arrangements of thermal fluid channel support contacts. Nu, channel resistance, heat transfer comprehensive performance coefficient PEC, and maximum plate pressure were simulated and calculated under different flue gas flow rates. The results show that compared with the prototype structure, the PEC value of the longitudinal arrangement structure of the hot fluid channel support contacts can be increased to 1.25. In the design condition, the pressure drop of the plate increases by 11%, the heat transfer performance is improved by 32%, and the plate pressure value is the smallest, which is the best improvement plan.