随着经济全球化和市场经济的深入发展，企业之间的通过股权、担保、互保、关联交易、金融衍生品、供应链及管理层的多重身份等形成错综复杂的关联关系，关联信用风险已成为现代企业风险管理的热点和难点问题。本文在小世界网络的框架下，提出了“基于关联企业群的小世界网络”的概念，应用平均场理论和传染病学原理，构建不完全免疫情景下的企业间关联信用风险的传染模型，揭示了关联企业群网络中关联信用风险的传染概率与不完全免疫及资产关联之间的关系，并进行了仿真实验。研究发现：在免疫失效和免疫失败共存的条件下，关联企业群网络中关联信用风险传染的临界值降低，从而增大了关联信用风险传染的可能性；关联企业群网络中企业间的资产关联关系和企业自身的免疫治理能力都将影响关联信用风险的传染和免疫效应。本文的研究对于预防和控制关联企业群中关联信用风险的传染具有重要的学术价值和现实意义。

With further development of economic globalization and market economy, enterprises form complicated relationships through equity, guarantees, mutual insurance, connected transaction, financial derivatives, supply chain and the multiple identities of management and so on. As a result, the associated credit risk has become hot and difficult problems in risk managements of modern enterprise. Under the framework of small world network, this paper proposes the concept of "small world networks based on the affiliated enterprises cluster network". we apply mean field theory and principle of epidemiology in order to construct associated credit risk contagion model between enterprises based on asset-related relationship under the imperfect immunization scenario, to reveal and simulate the relation among associated credit risk contagion probability with imperfect immunization and asset-related in enterprises cluster network. The study finds that the threshold value of the associated credit risk contagion is reduced under the condition of the immune failure and immune invalidity, thereby, increasing the likelihood of related credit risk contagion; and the assets correlation between enterprises will influence associated credit risk contagion and immune effect. The study of this paper is helpful for the prevention and control of the spread of the associated credit risk in the affiliated enterprises cluster, it has far-reaching academic value and practical significance.