In this paper,molded panels made of particles or fibers pre treated with steam was studied.Wood particles and fibers were treated with saturated steam at a pressure of 1 55 MPa for 4 min and 2 5 min respectively before molding.Testing results showed that the molded panels made of steam pre treated furnish had higher dimensional stability than that of control panels.Linear expansion of the panels made of treated particles,after cold water soaking treatment,was virtually dependent on resin consumption.Thickness swelling rate of the panels made of treated particles was reduced along with resin consumption increased in the range of 2 5%～7 5%。