中文摘要：

市政债券作为地方政府或其授权的代理机构从市场上筹集资金的长期债务性融资工具，用于偿还到期债务的资产或收入来源主要是地方财政收入或投资项目的现金流收益，而地方财政收入或投资项目的收益存在不确定性。因此，市政债券存在一定的风险。考虑到现实经济环境的不确定性，通过对KMV信用风险度量模型的改进，本文给出能够体现经济环境中不确定性的改进KMV模型，并结合市政债券的具体特点，具体分析了北京市政债券的信用风险和安全发行规模。

英文摘要：

Municipal bonds serve as long - term financing debt instrument from the market issued by local government or agencies warranted by the government. The main source of asset or income to pay debt receivable is local fiscal income or cash income of investment project which is uncertain. Therefore, municipal bonds might have risks. Considering the uncertainty of economic environment, model of KMV, this paper proposes a credit risk model with through improvement of the credit risk measurement uncertainty. Considering the specific characteristics of municipal bonds, we analyzes the credit risk and safe issuing size of Beijing municipal bonds.