The invention provides a welding method of a 9%-Ni steel annular butting welding bead of a low-temperature LNG storage cylinder. The welding method is characterized by comprising the following steps: step S100, designing a narrow-clearance butting groove provided with a truncated edge, wherein the butting groove is an X-shaped butting groove; and step S200, sequentially performing single layer backing welding, bottom strengthening welding, filler welding and cosmetic welding by utilizing a high-frequency hot-wire TIG welding method. By designing the type of the groove and selecting root welding, filler welding and cosmetic welding processes, the welding method provided by the invention can overcome the shortcomings that the prior art is low in welding efficiency, large in welding material consumption, numerous in welding bead defects, poor in welding joint performance, high in requirements on operation skills of a welder and the like, and has the characteristics of high welding efficiency, good welding bead quality, excellent welding joint performance and the like.