In our research, a commercial poly (lactic acid) (PLA) film was used in combination with wood fiber matrix to generate biodegradable composites by a film stacking technique and hot-press. The results showed the flexural properties and water resistance increased with the increasing of PLA addition. Silane-treated wood fiber composites significantly improved the flexural properties compared to untreated composites. In experiment range, the physical and mechanical properties of composites were better in higher hot-press temperature. The optimal parameters are determined by PLA addition 20%, silane addition 3%, the hot-press temperature 190°C, the hot-press time 10min.Under these parameters, the flexural properties of composites exceeded the requirement of the outdoor boards’ standard, but the water resistance was a little low.