1, construction permit (copy) 2. General and subcontracting qualifications, project manager, technical director and safety officer should have safety assessment certificates (stamped with official seal, copied and invalidated again, and indicated that only subcontracting filing procedures for a project are required) 3. Original general and subcontracting contracts (the contract is not signed by a legal person, and the power of attorney of the legal person is required) 4. Power of attorney of the subcontracting unit (entrusted)