Wood truss connected with metal plate is an important structural component widely used in modern timber structures. A new type of girder truss was developed and its bearing capacity and anti-deformation ability of light wood truss were studied. According to multi-stage loading test method specified in Standard for test methods of timber structures (GB/T 50329-2012), the deformation of 3 kinds of wooden trusses under standard design load and the ultimate bearing capacity during the destructive loading stage were compared. The test results showed that ultimate bearing capacity of wood truss is more than twice the standard design load which means the truss has great safety margin. During the course of design, the bearing capacity of the metal plate joints of the timber truss must be strictly checked to meet the basic requirements of corresponding bearing capacity of the truss. Several single trusses combined into girder truss by wooden dowel which have great synergistic effect can effectively solve the instability of the single truss. Wooden dowel joint is an effective connection for girder truss, which makes the bearing capacity of girder truss exceeds the sum of several single trusses and anti-deformation ability much better than single ones.