The invention discloses a combined bridge and a construction method thereof, involving bridge construction. The combined bridge includes a plurality of support members and a deck member, the support member comprises a plurality of fixing columns connected with the wooden bridge guardrail columns to be repaired through a connecting piece. The upper ends of the fixing columns are vertically connected with fixing blocks, and the lower ends are connected with support beams. The connector comprises a steel rope, two ends of the steel rope are connected through a joint, and the joint comprises two fixed seats which are fixed and connected side by side; the fixed seats are movably provided with U-rings; two ends of the U-rings are threadably connected with fixing nuts; the fixing columns are provided with a plurality of annular grooves; and the bridge deck member comprises a plurality of transverse bars. As a temporary bridge, the bridge is assembled by supporting members and bridge deck members, and the supporting members are attached to the guardrail columns of the original wooden bridge, so that the pile foundation is not required to be driven, the disassembly and assembly are fast andconvenient, and the load-bearing force is mostly borne by the original wooden bridge, so that the load-bearing capacity is strong and the stability is high.