An antibody combined with coagulation factor XI (FXI) and/or an activated factor thereof XIa (FXIa), or a fragment of FXI and/or FXIa, and a composition comprising the antibody. Further disclosed are a method for preparing the antibody, and use of the antibody in the preparation of medicaments for treating and/or preventing coagulation related diseases (e.g. thrombosis and thrombus-related complications or diseases).