Abstract: The thresholds of risk indexes are presented.A risk warning model by the signal theory and a risk prediction model by the gray system theory for SME credit guarantee institutions are set up.Based on those models,a comprehensive risk warning system for SME credit guarantee institutions integrating the pre-warning model and the prediction model is establised.The system is tested by examples.The comprehensive risk warning system will provide credit guarantee institutions an effective ways to control their risks.

Key words: credit guarantee institutiion, gray system theory, risk warning system, model