Legal basis: Article 7 of the Standard Provisions on Bidding Scope and Scale of Engineering Construction Projects, all kinds of 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 if they meet one of the following standards: 1, and the estimated price of a single construction contract is more than 4 million yuan. 2, the procurement of important equipment, materials and other goods, the estimated price of a single contract is more than 2 million yuan. 3, survey, design, supervision and other services procurement, the estimated price of a single contract is more than 6,543,800 yuan.