Abstract: Xiaertai group is a suit of metamorphic rocks outcropped in northern Liaoning Province and southern Jinlin Province, tectonically located in the south margin of Jilin-Heilongjiang orogenic belt. During the 1:50000 scaled regional geological survey, the theory of non-Smith stratum in orogenic belt is adopted, with structure analysis and ductile deformation zone research method, to systematically study the structural deformation of the strata. Aided by isotopic dating, three stages of structural deformation are identified. on this basis, the Archean metamorphic supracrustal rock unit is separated from original Xiaertai group. According to deformation features of the metamorphic series, the Xiaertai group is renamed as Xiaertai rock-group.