This thesis focuses on the analysis of the mean residual life regression model under semi-competing risks data. Under semi-competing risks data, since the non-terminal event time is dependently censored by the terminal event time, we can not make inference on the non-terminal event time without extra assumptions. Thus, we use the Archimedean copula assumptions to specify the dependence between the non-terminal event time and the terminal event time. Under the Archimedean copula model assumption, we adopt the mean imputation method and the median imputation method to impute the non-terminal event time. Then, we apply the method by Magulurit and Zhang (1994) to estimate the regression coefficient. We examine the performance of the proposed approaches by simualtion studies. We also apply our suggested approachs to analyze the Bone Marrow Transplant data.