Research conclusions: This analysis reveals：(1)The steel truss girder bridge main bar is mainly bearing the axial force，which is consistent with the design theory．(2)The effect of the spatial load transferring of the bridge is associated with the connection stiffness of the bars，the bar location and the load location，and to simplify the calculation of the load distribution between the two main trusses with the leverage method is safe．(3)Compared with the plane stress model，the stress of bottom chords calculated with the space beam element model is smaHer by 9．9％～16．4％，and the verification coefficient to compute statistics structure with the plane trussing model stipulated in the”Code for Inspection of Railway Bridges”only has the reference meaning．(4)Under the condition of main force combination，the actual stress of each test member is smaller than the design permission stress and has certain margin for safety．(5)The secondary stress of the member is proportional with the rigidity of the gusset plate and member．