The nature of open innovation is the mode innovation of knowledge creation and knowledge application, so the knowledge capacities are the key factor to implement open innovation. Although authors have separately carried on related researches to knowledge capacities and open innovation, they failed to bind them together commendably. Combining to predecessors' research results, the article puts forward the framework of knowledge capacities and ascertains six kinds of knowledge capacities: creative capacity, innovative capacity, scanning capacity, absorptive capacity, internalization capacity and desorptive capacity. For inbound open innovation, scanning capacity and absorptive capacity is important. For outbound open innovation, desorptive capacity is necessary. While there are higher requests to knowledge capacity under coupled process innovation. Of course, the core of open innovation is the co-creation of knowledge, so the creative capability of core knowledge is crucial in any case.