This talk provides an overview about the credit models for various structured credit products, and reveals the model risks in credit modeling, and the lessons from the financial crisis.    We use a few products and their modeling for illustration such as CDO/CLO, both rating and valuation models using BET and Gaussian copula,  SIV and using copula model in a multi-period setting, CDO^2 and its consistent pricing to the underling CDOs , and finally subprime mortgage modeling.   Some of the fundamental issues in structured credit product modeling such as the replication and equilibrium pricing will be discussed, and some future research topics will be highlighted.