The invention relates to a large-section U-shaped shield launching construction method. The large-section U-shaped shield launching construction method comprises the steps that site preparation is conducted before launching; a shield machine is assembled; a launching pilot tunnel is constructed; after being assembled, the shield machine is subjected to no-load debugging; a sealing device is mounted; the positions of opencut tunnel reinforcing sections and 0-ring segments are determined; an inner support and an outer support are mounted; after being assembled and launched at a launching site, the shield machine goes up a slope with the gradient being 0.3% firstly and then goes down the slope with the gradient being 0.3112% to the set position for receiving, and a shield tunnel is made to bein an inverted-V shape; and the segments are positioned and mounted. According to the construction method, through large-section loess tunnel shield construction, the technical problem of large-section tunnel shield launching construction is solved, and construction safety is guaranteed.