MNEs R&D institution is the key linkage of regional innovation system(RIS) and MNEs' global technology network,so it is an important resource for RIS.The interaction between MNEs R&D institution and RIS is the results of gamble by both sides and is beneficial to each other.The factors which affect the interaction includes,the nature of MNEs R&D institution,the technology level of indigenous principal parts,the technology drop height between indigenous and MNEs R&D institution,the supply of high quality R&D human,the protection of patent and the cluster of innovation principal parts.