A method for the mass production of human coagulation factor VII. The method includes a) providing an expression vector carrying i) a dihydrofolate reductase promoter devoid of one or more CCGCC repeat sequences from the GC-rich region thereof and a dihydrofolate reductase (DHFR) gene operably linked thereto and ii) a cytomegalovirus (CMV) promoter and a human coagulation factor VII gene operably linked thereto; b) obtaining a transformed a host cell line containing the expression vector; and c) culturing the transfected host cell in the presence of a dihydrofolate reductase inhibitor to select cells which express human coagulation factor VII with high efficiency; and d) adding sodium butyrate to the selected host cells.