The present disclosure relates to a method of manufacturing a cooling block for a hot stamping mold using a three-dimensional (3D) metal printer, and more particularly, to a method of manufacturing a cooling block for a hot stamping mold using a 3D metal printer including a process of first step for forming a plurality of semicircular channels through which a fluid passes on a lower block, and a process of second step for forming an upper block to form channels using a 3D metal printer respectively on the plurality of semicircular channels formed in the lower block along the plurality of semicircular channels.