The invention relates to a 
machining method of a group of holes in a large-sized 
metal tube plate. The 
machining method is used to manufacture 
metal tube plates for large-sized reaction vessels and heat exchangers in the 
petroleum and chemical industries. The 
machining method includes: 1, making a drilling procedure according to a design drawing, clamping the tube plate on a CNC (computer 
numerical control) boring and milling 
machine (or a CNC drilling 
machine, similarly hereafter), starting the CNC boring and milling 
machine, entering the drilling procedure, machining guide holes for all tube holes in the tube plate; 2, placing the tube plate flat on a support, with the guide holes facing up, adjusting the support to keep the surface of the tube plate horizontal, and firmly clamping the tube plate; placing three radial 
drilling machines outside the periphery of the tube plate, using each radial drilling 
machine to machine each 120-degree range of the tube holes in the tube plate, and using the three radial 
drilling machines to 
drill and ream the tube holes in the tube plate until a group of holes is obtained. The machining method has the advantages that machining of the group of holes in the large-sized 
metal tube plate is achieved with the CNC boring and milling machine (or the CNC drilling machine) and the radial 
drilling machines, equipment cost is low, work efficiency is high, and machining cost is low.