Abstract: The comparative study places the geological characteristics and evolution of Mongolia-Okhotsk fold system into the macroscopic framework of Paleo-Asian Ocean and peri-Pacific tectonic domains. It shows that the Mongolia-Okhotsk tectonic belt belongs to composite fold system. According to the main characteristics, the fold system can be divided into two parts. In the western part, the geological characteristics of Hangay-Kent-Daur fold belt in Late Neoproterozoic-Late Paleozoic are similar to the evolution characteristics of Paleo-Asian Ocean tectonic domain, with its tectonic evolution in Early Mesozoic related to the continental disintegration after the plate convergence of Paleo-Asian Ocean tectonic domain and large-scale strike slip and thrust superimposed in Late Mesozoic. While in the east, the main fold system is part of the Mesozoic tectonic evolution of peri-Pacific active continental margin, with the Mesozoic continental arc basin system and large strike-slip fault zone in its western sectiont superimposed on the paleo-Eurasia Plate and Paleozoic fold belt and the Middle Late Jurassic-Early Cretaceous Uda-Murga continental margin fold-thrust belt in its eastern section cut obliquely and covered by Late Cretaceous Sikhot-Alin and Okhotsk-Chukchi continental margin volcanic belt.