The invention provides a modularization steel die trolley and a construction process thereof. The trolley comprises an inner die trolley and an outer die trolley. The inner die trolley is of a semi-closed steel structure and comprises a support elevating system and a walking system. The outer die trolley also comprises the same support elevating system and the same walking system. The inner die trolley also comprises a support template. The outer die trolley also comprises a support system, an outer support template and a lead screw. According to the invention, one set of special outer die trolley door frame can be used with multiple sets of common template assemblies.