Using a sample of 1250 companies listed in Shanghai or Shenzhen Stock exchanges for the time period from 1999 to 2010, we find that for firms with a higher level of uncertainty, the benefits of the connections and advice provided by directors outweigh the costs of the impairment in decision making related to having a large board size. In particular, the positive incremental effect of board size on Q, for firms with a higher proportion of State shares, suggests that connections provided by directors is crucial for firms to get access to greater resources and it is even more important to Stateowned than to Non-State-owned firms during the economic reform in China. Our results indicate that that both agency theory and resource dependence theory play an important role on board efficient research.