The invention discloses a paper conveying device of a printer. The paper conveying device comprises a rack, a paper feeding roller, a paper pressing wheel, a paper pressing brush, a paper pressing framework, a paper conveying plate, a paper pressing roller, a paper pressing brush roller, a paper pressing ball, a paper delivery tooth-shaped table, a paper pressing sheet, a gas suction nozzle, a connecting rod, a conveyor belt, a tensioning arm, a valve body, a blocking plate, a side guide paper-pressing sheet, a side guide pulling plate, a front paper pressing sheet and a front guide, wherein the end part of the rack is fixedly equipped with the paper feeding roller; the paper pressing wheel is movably connected on the paper feeding roller; the paper conveying plate is fixedly mounted on the rack; steel plates are arranged on the paper conveying plate; a transmission belt is correspondingly mounted on each steel plate; the front end of the paper conveying plate is equipped with the gas suction nozzle; the paper pressing framework is mounted on the rack above the paper conveying plate; the tensioning arm is fixedly mounted at the outer side of the rack; and the conveyor belt outside the rack passes through a tensioning arm slide wheel. The paper conveying device is reasonable and simple in structure, is convenient to use, and effectively stabilizes paper, so that paper flatly reaches the front guide, normal production assembly operation is met, production efficiency is improved, and use is flexible and convenient.