According to the method of accumulate the timber,put the timber into the kiln after finish cutting the wood.The airflow heat up because of the fan driving during the work time, then the airflow pass through the timber space, transmit the heat to the timber, and take away the steam evaporate from the timber at the same time.Improve the humidity of medium in kiln, when the medium humidity higher than the standard, open the exhaust valve, eliminate part of the moisture, and suck the outside air corresponding at the same time, when the medium humidity reach the standard, close the exhaust valve.When the medium humidity in the kiln is under the standard, open the steam valve, let the steam pipe spray out the steam, after the medium humidity improve and fit the standard, close the exhaust valve. In this way, the cycling system working repeatedly until it reach the drying standard. In order to drying the timber uniformity, the fan should change the direction at regular time, to form the reversible cycle airflow.