The applicable conditions, equipment matching, construction technology and relevant technologies of milling excavation machine are discussed in detail. The construction technologies, construction effect, control of surrounding rock settlement, exiting problems, items should be paid attention to and improved technologies of milling excavation machine used in large crosssection tunnels located in different geological conditions are analyzed and discussed. The milling excavation method is an economic and effective method under strict limits. It can improve the mechanization of tunnel excavation in China.