中文摘要：

金融市场摩擦对于解释宏观经济波动具有重要作用。本文在动态随机一般均衡模型的分析框架下，采用贝叶斯方法对外部融资溢价和抵押约束这两种金融摩擦进行比较研究．发现由于存在宏观层面的信贷规模控制和微观层面的信贷配给，抵押约束机制这种数量型金融摩擦比外部融资溢价这种价格型金融摩擦更适合描述中国信贷市场，能够显著提高模型对中国经济数据的解释能力。此外，本文还通过冲击一响应分析和方差分解比较了这两种金融摩擦对经济波动的不同影响。

英文摘要：

Frictions in financial market plays an important role in explaining the macroeconomic fluctuations. This paper compares two different financial frictions-external finance premium and collateral constraint, by introducing them into DSGE models. Result of Bayesian model comparison shows that, collateral constraint model is more in line with Chinese data than external finance premium model, because there is credit control in macroeconomy and credit ration in microeconomy in China credit market. In addition, we analyze the impacts on macroeconomic fluctuations of these two financial frictions by using impulse response analysis and variance decomposition.