The invention relates to the field of construction engineering, in particular to construction strengthening and modification and discloses a method for strengthening a wood beam. The method for strengthening the wood beam comprises the following steps of: (1) performing surface evenness treatment on a stressed surface of the wood beam, scrubbing with acetone, and if a bottom face has a crack or recess, mending by adopting mending glue; (2) selecting bamboo chips which are treated by surface processing and are 3 to 7 millimeters thick, 10 to 25 millimeters wide and as long as the wood beam, and scrubbing with the acetone; and (3) coating base glue on the drawn face of the wood beam, adhering at least one layer of bamboo chips on the stressed surface of the wood beam by using structural glue and pressing to ensure that the bamboo chips, the structural glue and the wood beam are bonded compactly. The method can effectively avoid dismantling the original structure, guarantee the bearing capability and durability of the wood beam and meet the subsequent use requirements. The bamboo chip is a regenerative material and has high anti-drawing strength, so that the resource and energy consumption of the construction strengthening and modifying industry can be effectively reduced by using the bamboo chips to strengthen the wood beam.