Abstract: Two disadvantages exist in the direct-fire type dryer for particles in particleboard factories at home today, namely, the possible pollution by the unburned coal dust and the accidental fire that may occur in particles in the rotary drum. In order to raise its efficiency, some improvements have been made in four respects:(1) An additional wall has been placed in the combustion chamber, which greatly decreases pollution and keeps away the fire from particles.(2) The rotary drum has been broken down into two parts, so that difficulties in manufacturing, installing and repairing a dryer for a medium or small sized factory would be reduced.(3) A SCR stepless speed regulator has been introduced in the dryer. The speed of the rotary drum can be adjusted in the range from 2-16 r. p. m.(4) A simple device for controlling fire has been added to the dryer to make the temperature of the mixed gas in the rotary drum to be always below the burning point of particles.This improved new type dryer has been put to use in particleboard factory for over two years. Its efficiency and properties have proved much better than those of the old type.