Abstract: Surface roughness is an important parameter of surface quality in the course of panel furniture manufacturing. In this study, the parameters of surface roughness of medium density fiberboard (MDF) such as average roughness (Ra), maximum individual peak-to-valley height (Ry) and mean peak-to-volley space (Sm) were measured with outline testing method during the different 15 stages after being sawed. The result indicated that the parameters of Ra、Ry and Sm were influenced by leaving time. Ra and Ry have a definite positive linearly correlation with leaving time. Sm has a negative linear correlation with leaving time. It was concluded that the surface roughness of board displays linearly relation with leaving time after being sawed. It was helpful in the determination of the processing time of following procedures in manufacturing.