According to Article 3 of the General Principles of the Bidding Law of People's Republic of China (PRC), the following engineering construction projects, including engineering survey, design, construction, supervision and procurement of important equipment and materials related to engineering construction, must be subject to bidding: 1. Large-scale infrastructure, public utilities and other projects involving social interests and public safety; Two, all or part of the use of state-owned capital investment or state financing projects; Three, the use of international organizations or foreign government loans and assistance projects.

According to the former State Planning Commission's Standard Provisions on the Bidding Scope and Scale of Engineering Construction Projects (Order No.3 of the State Planning Commission), engineering construction projects include survey, design, construction, supervision and procurement of important equipment and materials related to engineering construction. Anyone who meets one of the following criteria must be invited to bid: 1. The estimated price of a single construction contract is more than 2 million yuan; Two, the procurement of important equipment, materials and other goods, the estimated price of a single contract is more than 6,543,800 yuan; Three, survey, design, supervision and other services procurement, the estimated price of a single contract is more than 500 thousand yuan; Four, the estimated price of a single contract is lower than the above standard, but the total investment of the project is more than 30 million yuan.