In order to investigate heat transfer and resistance characteristics of H-type finned tube in the low pressure economizer, realizable turbulence model was adopted to analyze flow and heat transfer characteristics of flue gas covered by H-type finned tube. The results show that the H-type finned tube can make the airflow become uniform; the vortexes formed on the wall are favorable to enhance heat transfer because of detouring flow in the channel; the higher velocity of flue gas is, the larger heat transfer coefficient of H-type finned tube and flow resistance will be; with the increase of pitch of the finned tube, the heat transfer coefficient increases, flow resistance decreases; when the pitch of H-type finned tube is 18 mm, the value of heat transfer coefficient reaches a peak and flow resistance is smallest. Therefore, the selection of 18 mm-pitches H-type finned is most economical.