The invention relates to a targeted platelet membrane glycoprotein GPIbalpha monoclonal antibody for inhibiting tumor metastasis. The monoclonal antibody is a monoclonal antibody that the specificity thereof is combined with a platelet membrane protein GPIbalpha. The invention also relates to a method for screening a tumor metastasis inhibitor of a targeted platelet membrane glycoprotein GPIbalpha. The method comprises five steps of: 1, establishing an initial screening model by using an enzyme-linked immunosorbent assay; 2, establishing a secondary screening model with Western blotting; 3-5, establishing a functional detection model with a flow type cytometer and a continuous spectrum luminoscope. The established screening model significantly reduces the need for human-derived platelets during the process of acquiring the targeted platelet membrane glycoprotein GPIbalpha inhibitor and maximizes the activation of tumor cells in a vitro experiment, simulates the microenvironment of the tumor cells and improves the screening accuracy, and the obtained antibody YQ3 has a good clinical application prospect.