Through the credit guarantee contract model considered with the guarantee rate and counter guarantee measure value, it is proved in theory that when the expected revenue of lower risky SME is zero, the guarantee rates accepted by the high risky SME and the low risky SME are equal and the counter-guarantee measure value provided by them are the same too; when the expected revenue of lower risky SME is non-negative, the higher risky SME are willing to accept lower guarantee rate and provide higher counter-guarantee measure value, while the lower risky SME are just the opposite. The credit guarantee institutions can utilize guarantee rate and counter-guarantee measure value as the mechanism to separate the risk type of SME. It can judge the risky type of SME exactly through SME with different risk selecting guarantee contract in order to make the guarantee contract more scientific and reasonable.