An empirical research based on a sample of 875 listed manufacturing companies is conducted, and the relationship among organizational slack, network position and diversification strategy is discussed in the context of interlocking directorate network. Organizational slack is classified as available slack, recoverable slack and potential slack. Degree centrality and structure holes are employed in measuring central position and broker position. The empirical results indicate that organizational slack and diversification are positively related and the moderating effects of network position depend on different type of organizational slack.