Service class

（1）Construction service: the suppliers providing supervision, bidding agency, cost consulting and other professional services.
（2）Design service: the suppliers providing design, and professional consulting.

Engineering class

It refers to the suppliers undertaking new construction, reconstruction, expansion, decoration, removal, renovation and etc of part or whole building and structures; according to the importance of the management and different contracting range, the engineering suppliers can be divided into two categories:
（1）Main-contractor supplier: the construction enterprises providing general contracting services for housing construction project (namely, "general civil engineering project"); according to qualification, which can be divided into super class, primary class, secondary class, third class, so as to undertake the different range of project;
（2）Sub-contract suppliers: other professional construction enterprises undertaking the projects beyond the “general civil engineering project”, including foundation subcontracting, curtain wall subcontracting, electromechanical subcontracting, refined decoration subcontracting, fire control subcontracting, weak current subcontracting and landscape gardening and etc. According to the different contracting ways, it can be divided into “independent subcontracting" and "subcontracting assigned by party A".

Material and equipment class

It refers to the suppliers providing the materials, equipments and other forms and types of products and related supporting services, including goods manufacturers, cargo agents, etc.