The present disclosure relates to an antibody specifically binding to bovine pregnancy-associated glycoprotein 1 (bPAG1) or an antigen-binding fragment thereof. The present disclosure further relates to a hybridoma cell producing the antibody; a composition including the antibody as an effective ingredient for diagnosis of bovine pregnancy; and a kit for diagnosis of bovine pregnancy. The present disclosure also relates to a method of diagnosing bovine pregnancy. Binding specifically to bPAG1, which is a pregnancy-associated plasma protein in bovines, the antibody allows a simple diagnosis of pregnancy in animals such as bovines of which the reproduction is important, so that the antibody may be usefully applied in the livestock industry by increasing reproduction efficiency.