Nickel base single crystal superalloy is a complex alloy containing 10~15 elements, with excellent high-temperature strength and corrosion resistance. Almost all turbine parts of advanced gas turbine engines use single crystal blades with hollow structures. During their service, they must bear high temperatures hundreds of degrees Celsius above their metal melting temperature and huge centrifugal tensile stress. They are aviation parts with the worst working conditions and are known as the “pearl on the crown”. The development of more high-temperature resistant blade materials and the improvement of blade cooling technology are key to improving the turbine gas temperature. Many dense refractory elements such as Ta, W and re are added to the new generation of single crystal blades to improve the temperature resistance. These elements have serious dendrite segregation during solidification, resulting in uneven distribution of components in the microstructure. Complex step-by-step heat treatment is usually used to dissolve the non-equilibrium structure and reduce segregation. The detailed characterization of dendrite composition is of great significance in optimizing heat treatment and blade design. Microbeam X-ray fluorescence spectroscopy is a nondestructive testing technology. It is simple to prepare samples without plating conductive film and can provide information on the distribution of deep components of samples. It can detect multiple elements simultaneously. It is mostly used in biological and archaeological fields. It is not easy to characterize metal materials with complex components quantitatively, and there are few application cases. Single crystal superalloy has a special cross-dendrite structure with a size of hundreds of microns. Microbeam X-ray fluorescence spectroscopy can meet the needs of detailed characterization of single crystal blade dendrite composition and quantitative statistics of composition distribution in a large area. The quantitative statistical distribution characterization method of dendrite composition of nickel base single-crystal superalloy was established based on microbeam X-ray fluorescence spectroscopy. This method is applied to the quantitative distribution characterization of the global dendritic structure of the new single-crystal turbine blade, the evolution law of the composition from the crown to the tenon of the single-crystal turbine blade is discussed, and the primary segregation ratio and secondary segregation ratio of the key alloy elements in different parts are obtained. The results show that for the elements Re, W and Ta with serious segregation, the segregation degree of each element from blade crown to tenon gradually decreases with the increase of blade section size and the distance from the blade to cooling copper disk, and the reduction degree of secondary segregation ratio is greater than that of primary segregation ratio. The segregation ratio of Cr, Co and Mo elements is close to 1, the segregation change is not obvious, and the distribution is uniform.