The present invention relates to a construction method and a structure for water and electric pipe arrangement in the same layer and mute insulation wall structure in a building. The floor and the exterior wall structure are divided into structural layer and decoration layer. The structural layer is constructed in accordance with the original design thickness and reinforcement. The main material for the decoration layer is an expanded polystyrene composite board having good sound-absorbing characteristics. By using the quickly melting characteristic of the expanded polystyrene in a fire, melting expanded polystyrene on the pipeline arrangement position in expanded polystyrene composite boards, then piping the pipeline in the melted position of the expanded polystyrene board to simplify the plumbing construction program of exposed pipes of water and electric pipes; and the water and electric pipe arrangement in the same layer, mute floor and roof insulation in the building can be effectively solved, without the problem of complicated construction in traditional exposed pipe construction hanging operation.