Legal subcontracting: The contractor of the contract may entrust part of the work contracted by himself to a third person, but must obtain the consent of the employer. The part of the work subcontracted by the Contractor can only be non main structure tasks, and the subcontractor must have the corresponding qualification level. Subcontracting can only occur once, and it is prohibited to subcontract again.
 [Legal Basis]
 According to Article 29 of the Construction Law, the general contractor of construction projects can contract part of the contracted projects to subcontractors with corresponding qualifications; However, except for the subcontracting agreed in the general contract, it must be approved by the construction unit. In the case of general contracting, the construction of the main structure of the construction project must be completed by the general contractor itself.