All materials entering the construction site must have factory certificates. However, because the materials used are more or less, the purchase channels are different, and the same batch of ex-factory materials are supplied to several different projects, there is a problem of using copies. The Standard for Acceptance of Construction Quality of Building Engineering stipulates that the contents of certificate of approval, test (inspection) inspection sheet or record sheet should be complete, accurate and true; The copy shall indicate the original storage unit, and shall be signed and sealed by the writer and the copy unit. However, in engineering, copies are often used directly as the vouchers and filing materials for materials entering the site. In fact, because the same batch of materials is supplied to several different projects, the quantity and tonnage of materials used in the project are inconsistent with those indicated in the photocopy, which cannot reflect the name and location of the project and accurately reflect the actual situation of materials used in the project. Therefore, the certificate is not targeted and legal, and cannot be used as the basis for material qualification certification and filing materials. Then, if photocopies or photocopies are used as qualification certificates and filing materials for materials entering the site, the following related contents shall be listed in detail: project name, parts used in the project, specifications, varieties, quantities, entry time, original storage place, signature of the manager and seal of the original storage unit and the copy or photocopy unit. For project supervision, project supervisors must also realize that.