中文摘要：

董事会在公司治理中的作用得到了代理理论和友好董事会理论的广泛且富有成效的论证，而最近的灰色董事理论则致力于分析独立董事与CEO之间的社会关系及其对董事会功用的影响。本文构建了一个统一的理论模型，分析了股东、董事会和CEO之间的三阶段博弈，考察了灰色董事的监督和建议功能。结果发现，CEO和董事之间的关系可以削弱对企业的监督行为，但会增强建议行为，且该建议功能随着CEO持股比例的增加而增加；大股东和董事之间的关系不仅不能解决委托代理问题，反而有可能加剧大股东对小股东的掏空行为。

英文摘要：

The researches focusing on the function of independent directors have evolved over three stages： the agent theory, friend board directors and the grey board directors whose thief concern is ：the connections between CEO and directors of board. This paper builds a theoretical model to study the inter- actions between stock holders, directors and CEO in a unit framework. The main focus is to study the effects of grey directors on supervising and advising function of board of directors. Our results show that the connections between CEO and directors of board reduce the supervising function of the board, but can enhance the advising ability of board. Moreover, this advising function increases with the CEO owing a higher share of stocks. However, the connections between large shareholder and independent directors cannot resolve the first agency problem, instead it may worsen the second agency problem.