The relation among six factors (particle size and particle geometry, board density, resin consumption, prepressing temperature, closing time and compressing thickness) and particleboard mat spring back after prepressing was studied. The results showed that wood properties and particle’s rigidity decrease were the main reasons of the spring back; and that all of reconstituting factors (particle size and particle geometry, board density, resin consumption and prepressing factors) affected the spring back. It concluded that proper technological counter measure could be adopted to reduce the spring back.