Morphological and anatomical characteristics were observed during the formation of adventitious roots of Platycladus orientalis with paraffin method, external morphological changes, origin and formation process of adventitious roots were analyzed. We also discussed the occurrence pattern and histological origin of adventitious. The results showed that, adventitious roots protruded from callus and skin, including callus rooting type, cortex rooting type, both callus and cortex rooting type. We also found few latent root primordia in stem cutting, but most of the roots were formed on primordial induced from callus, xylem, vascular cambium and secondary phloem. Through our research, we consider the formation of adventitious root primordial of P. orientalis belong to multilocus models, and the histological origin adventitious is callus, pith ray, ray primitive cells and undifferentiated xylem cells. Simultaneous activation of these root origin sites through artificial induction can significantly improve rooting rate and rooting quality.