Huatailong attaches great importance to safety supervision of outer cooperative unit for construction, e.g., they adopt strict security access system, strengthening authenticity affirmation of all kinds of the construction unit’ s certification to prevent borrowing or illegal use of other’ s qualifications to participate in contracting projects; they will sign safety production management agreement with the construction unit to clear security responsibilities and obligations, safety investment and financing guarantee, hidden danger checking and governance, accident emergency rescue, the responsibility of the breach of agreement and other matters; meanwhile, they strictly implement the system of production safety risk mortgage capital and collect the production safety risk mortgage capital of the outer construction unit according to a certain proportion of the total amount of the project contract.