legal ground
People's Republic of China (PRC) building law
Twenty-ninth general contracting units of construction projects may contract some contracted projects to subcontractors with corresponding qualifications; Except for subcontracting agreed in the general contract, it must be approved by the construction unit. In the case of general contracting, the main structure construction of the construction project must be completed by the general contracting unit itself. The general contractor of a construction project shall be responsible to the construction unit in accordance with the provisions of the general contract; Subcontractors shall be responsible to the general contractor according to the provisions of the subcontract. The general contractor and subcontractors shall bear joint and several liability to the construction unit for the subcontracted project. It is forbidden for the general contractor to subcontract the project to units that do not have the corresponding qualifications. Subcontractors are prohibited from subcontracting contracted projects.