Abstract: It has a positive impact on improving their radical innovation performance for SMEs in KIBS to use their network capability to acquire the organization tacit knowledge from external social network. Based on a theoretical analysis and an investigation into 213 SMEs in KIBS in Zhejiang Province via questionnaire and empirical study, it is found that the capabilities of network visioning, constructing, operating and orienting all have a significantly positive effect on the organization's cultural tacit knowledge acquisition and the organization's embedded tacit knowledge acquisition; both kinds of organization's tacit knowledge acquisition have significantly positive effect on the radical innovation performance; the organization's tacit knowledge acquisition plays a partial mediation role in the relationship between network constructing capability and radical innovation performance, as well as between network operating capability and radical innovation performance; organization tacit knowledge acquisition wholly mediates the relationship between network visioning capability and radical innovation performance, just as what it does between network orienting capability and radical innovation performance.

Key words: network capability, organization's tacit knowledge acquisition, radical innovation performance, knowledge-intensive business service (KIBS), small-and-medium-sized enterprises (SME)