The invention relates to a competitive ELISA method based on a foot-and-mouth disease A type VP1 protein and its monoclonal antibody, also relates to a preparation method of the foot-and-mouth disease A type VP1 protein, and a preparation method of the monoclonal antibody of the foot-and-mouth disease A type VP1 protein, and belongs to the technical field of animal immunological detection. In the invention, a primer pair C1 and C2 and a primer pair E1 and E2 are amplified to obtain a gene sequence of the foot-and-mouth disease A type VP1 protein, the foot-and-mouth disease A type VP1 protein is obtained by constructing an expression plasmid, introducing the expression plasmid into a prokaryotic expression host and carrying out inducible purification, the foot-and-mouth disease A type VP1 protein monoclonal antibody is obtained by treating the foot-and-mouth disease A type VP1 protein as an antigen through a hybridomas technology, and the competitive ELISA method used for detecting a foot-and-mouth disease A type antibody is established based on the foot-and-mouth disease A type VP1 protein and its monoclonal antibody. The detection method has a strong specificity and a good stability, and can be used for detecting a foot-and-mouth disease A type serum antibody. By comparing a result obtained through the detection method with a liquid phase blocking ELISA kit, the coincidence rate is 95.8%.