Abstract: An enterprise group is a multi-corporate union.It may consist of a parent company,its subsidiaries,associates and branches.As the major client of commercial bank,a member of enterprise group defaults may lead to the default of the other member of enterprise group.This contagion effect exposes banks to huge cumulative credit risk.It is an important part for banks to control the correlative default risk in enterprise group.Based on the intensity model,we think that the variable of enterprise group's asset value is a public factor of the default intensity of the subsidiaries,and design a model for measuring the correlation of default of the related corporations under the control of parent company The research shows that default correlation of the related corporations positive with the ratio of equity holding by the parent company,but the impact of the change in equity holding ratio isn't significant.

Key words: enterprise group, default intensity, default correlation, ratio of equity holding