Abstract:     By forming and operating knowledge networks, incubators can help incubating enterprises fill their knowledge gaps and achieve innovation incubation performance. However, the practical scenarios are quite different. Some incubators have successfully shaped the brand of knowledge service and become the industry benchmark, but some of them are trapped in the dilemma of homogenization and fail to provide satisfactory function of innovation incubation.  In this study, we believe that the differentiated innovation incubation performance is not only related to the type of incubator knowledge service, but also depends on the behavioral choice and trait attributes of the incubator. Based on the perspective of active feedback to knowledge services, this study distinguishes knowledge services into two types: normative and endorsement. Among them: in the normative knowledge service, the incubator plays the role of controller, monitors the participants′ knowledge cooperation process, and ensures that the knowledge flow conforms to the preset rules and procedures. In the endorsement-type knowledge service, the incubator plays the facilitator role, emphasizing the autonomous interaction between the incubating enterprises and the key knowledge holders. Moreover, with the acquisition learning as the mediator variable and the entrepreneurial alert as the moderator, this study constructs a model of incubator knowledge service impact innovation incubation performance, trying to clarify the differential impact of different knowledge service types on innovation incubation performance from the perspective of knowledge service affecting the process mechanism of Innovation incubation performance.
    This study collected empirical data by conducting a questionnaire survey of 376 incubators in 54 incubators in Changzhou City, Jiangsu Province. The sample selected technology-based business incubators and technology-based incubators with more prominent knowledge service activities. After testing the reliability and validity of the sample data, this study used cross-level regression and Bootstrap methods to make hypothesis tests on the direct, mediating, regulatory, and regulated mediating effects of the study by SPSS and MPLUS software. The results showed that: There is an inverted U-shaped relationship between normative knowledge services and the innovation incubation performance while the endorsement knowledge service has a positive impact on the innovation incubation performance; The acquisition learning of the incubating enterprises play an intermediary role, which not only enhances the inverted U-shaped relationship between normative knowledge service and innovation incubation performance, but also convey the positive impact of endorsement knowledge services on innovation incubation performance; Entrepreneurial alert not only positively regulates the relationship between acquisitive learning and innovation incubation performance, but also regulates the mediating effect of acquisitive learning.
     This study has important enlightenment for the incubator to improve the quality of knowledge service: First, incubators should not give too much intervention to incubating enterprises in the process of knowledge service. The intervention is easy to be considered as noise, or the relationship breaker. In contrast, incubators should highlight the identity of third-party mediators and focus on enhancing interaction between participants in the incubation network. However, what is important is not the choice of normative knowledge service and endorsement knowledge service, but how the incubator can successfully complete the identity switch between the leader and the intermediator in the innovation incubation according to the needs of the incubator innovation.
     Secondly, the incubator should implant professional help for the knowledge absorption and secondary information process of incubating enterprises in form of knowledge services. Taking the acquired learning of incubated enterprises as an opportunity, incubators can help incubating enterprises correctly use the decentralized innovative learning resources in the network to complete their own leveraged growth.
     Finally, the role of entrepreneurial alertness should be paid more attention. The new-born weakness of the incubating enterprises makes it difficult to identify effective entrepreneurial opportunities by their own vigilance. Therefore, the incubator should strive to promote the interaction of knowledge and information among members by the special improvement of sharing atmosphere, communication channels and maintenance of relationships.

Key words:  knowledge service, acquired learning, entrepreneurial alert, innovation incubation performance