Absorptive capacities are the deter mi nants of success of open innovation . This paper analyzes the key influencing factors of absorptive capacity . The absorptive capacities of external knowl edge are low in Chinese enterprises . This paper shows that the position of firms in the innovation network , the channel for acquiring external knowl edge , the frequency of external contact are deter mi nants of potential absorptive capacity . The relationship of social capitals and the attributes of external knowl edge are deter mi nants of actual absorptive capacity . In addition to those mentioned above , firms' knowl edge base , R&D intensity , the learning intensity and learning methods of employees , open culture and learning mechanism are all important influencing factors . At last , this paper puts for ward some suggestions for enterprises toimprove the absorptive capacity .