The invention discloses a polycrystalline silicon reduction furnace and a method for growing polycrystalline silicon by using the polycrystalline silicon reduction furnace. A furnace chamber of the polycrystalline silicon reduction furnace is partitioned into at least two sub furnace chambers through a partition plate; an opening is formed in the partition plate; the opening gets close to the furnace top or the furnace bottom of the furnace chamber, an air inlet for air inflow is formed in one of the sub furnace chamber, and an air outlet for air exhaust is formed in the at least one remainingsub furnace chamber; feed air introduced into the sub furnace chamber provided with the air inlet flows into the adjacent sub furnace chamber through the opening in the partition plate, and feed airinside the sub furnace chamber provided with the air inlet and feed air inside the adjacent sub furnace chamber are opposite in flowing directions. The sub furnace chambers become plug flow reactors,the feed air flows inside the sub furnace chambers in one direction, and an airflow inside the sub furnace chambers is prevented from being disturbed in opposite direction, so that the distribution ofthe flow rate and temperature of the air flow is more uniform from the roots to the tops of silicon robs inside the sub furnace chambers, particularly, a viscous flow phenomenon around cross beams ofthe silicon rods is eliminated, and the materials of the cross beams are reduced.