Restricted bidding, also known as negotiation bidding or negotiation bidding, refers to that for some projects (projects) with complex technology or urgent construction period, two or more legal persons or other organizations interested in bidding are selected to issue bidding invitations after obtaining the consent of the relevant competent departments, and then the bidding method of the winning bidder is determined through negotiation.

Restricted bidding is also called: negotiation bidding or negotiation bidding is suitable for improving efficiency and reducing costs: only a limited range of suppliers can be purchased. Also called selective bidding and invitation bidding. This method is suitable for the limited number of potential suppliers or to improve efficiency and reduce costs. It is a variant of public bidding, and it is a modification and supplement to public bidding for different procurement environments. Its advantages are faster, lower cost and higher efficiency than public bidding, but its disadvantage is that it is not as competitive as public bidding, especially in the process of selecting suppliers who invite bidding. In order to prevent this method from being abused, its applicable conditions can be limited to one of the following situations: ① the procurement project is complex or special, and it can only be purchased from a limited range of suppliers; (2) The value of the procurement project is low, and the research and review of the bidding documents takes a long time and costs a lot. The buyer can only save money by limiting the number of bidders. In addition, in view of China's Bidding Law, bidding can be divided into open bidding and invitation bidding. For the convergence and unification of laws, the name of this method should be determined as invitation to bid.