Abstract: In the era of digital economy, some leading enterprises build the open innovation community (OIC) in order to tap collective wisdom from global innovators, which helps to overcome the innovation problems. However, Chinese enterprises set up the OIC later, most OICs fail to produce enough collective wisdom. Thus, for many enterprises, it is generally not easy to obtain expected benefits from OICs. Therefore, how to stimulate the emergence of collective wisdom in OICs in order to improve the enterprises innovation level is the important issue.Based on the theories of knowledge management and ecology, the evolutionary process of the collective wisdom is analyzed. The collective wisdom in OICs stems from multi-agent knowledge interaction. The participants of knowledge interaction mainly include enterprises and users, and users can be further divided into leading users and ordinary users. According to the differences of the participants in OIC, the OIC is classified into two kinds, one is the "user-led" community, and the other is the "user-led with enterprises guidance" community. When analyzing the mechanism of emergence of collective wisdom in OICs, several factors are taken into considerations, includingthe existing knowledge stock, maximum knowledge capacity, knowledge openness and knowledge absorption capacity of different participants. Then, the two-dimensional and three-dimensional Lotka-Volterra ecological evolution models are constructed respectively, and the stability of above models is analyzed. Three conclusions are drawn through theoretical analysis and numerical simulation. Firstly, in the "user-led" OIC, the emergence of collective wisdom mainly depends on the knowledge openness and knowledge absorption ability of both ordinary users and leading users. Because the enterprises have not opened the necessary knowledge to the OIC, the level of collective wisdom is tended to stay at a low-level stage. Secondly, in the "user-led with enterprises guidance" OIC, enterprises open their knowledge to users, and the level of collective wisdom is significantly improved compared to the "user-led" OIC. So a certain degree of knowledge openness is significant for OIC to stimulate the growth of collective wisdom. Thirdly, the level of collective wisdom will also be affected by the ecological relationship of users. When users are under the ecological relationship of reciprocal symbiosis, the effect of enterprises' knowledge openness will be improved, and the level of collective wisdom is higher. When users are under the ecological relationship of partial benefit symbiosis, the effect of enterprises' knowledge openness will be weakened, and the level of collective wisdom is lower.This research will enrich the theory of open innovation, and it is helpful for enterprises' managers to optimize knowledge management.

Key words: open innovation communities, Lotka-Volterra model, knowledge openness, collective wisdom, ecological evolution