How to evaluate network management capability is one of important research topics about network management. This paper proposes a novel quantity evaluation method of network management capability, Network management capability model. In this paper, key factors about network management capability, such as network resource gross, distribution, heterogeneity, available resource, network management cost and ability of management technologies, are discussed. A causal loop diagram of network management capability and related expressions are also designed. Finally, as an application of network management capability model, capability of self-management for the management of large-scale, distributed and heterogeneous networks is evaluated.