Abstract: Liaohe group, outcropped in Eastern Liaoning Province, is a unique series of Paleoproterozoic metamorphic rocks, abundant in mineral resources. There has been a long history of research on the group, but arguments still remain about some key problems on the metamorphism of Liaohe group. This paper applies the theory of P-T-t trace in these problems. It is concluded that the basic reason for the metamorphism of Liaohe group was the subduction of the group caused by continental collision and orogeny. The evolving characteristics of the metamorphism are temporally and spatially unique. The metamorphism of Liaohe group varies with structures in different scales or levels.