Purpose: This study was designed to construct a structural model to explain the quality of life of grandmothers caring for their grandchildren. Method: Data were collected by self-report questionnaires from 232 grandmothers caring for their grandchildren living in Busan. The data collection period was from June to Oct. 2006. Data analysis was done with SAS 9.13 for descriptive statistics and PC-LISREL 8.52 program for Covariance Structural analysis. Results: The findings found that the fit of the hypothetical model to the data was good, but considering theoretical implications and statistical significances of parameter estimates, paths and variables of the model were modified by excluding 2 paths. The Modified Model with 17 paths showed a good fitness to the empirical data ($X^2=15.492$ (df=11, p=.161), GFI=.985 AGFI=.940 NFI=.982 RMSR=.037 RMSEA=.042). Health status, health problems, economical status, life events, caring stress, caring efficacy and life satisfaction had significant effects on quality of life in the grandmother caring their grandchildren, but of these variables, self-esteem was the most essential factor. All predictive variables of quality of life together explained 63.9% of the variance. Conclusion: The derived model in this study was confirmed to be proper in explaining and predicting the quality of life of the grandmothers caring their grandchildren.