This model envisions the Model of Maqasid al-Shariah (MMS) for decision-making process in critical medical treatment. The underlying principle is the preservation of life as the central objective in Islamic biomedical ethics and how significance of this objective influences the decision in medical interventions. There are three medical cases extrapolated for this purpose; abortion of pregnancy with thalassemia risk, termination of support system in brain death, Bariatric surgery for morbid obesity patients. The method adopted is visual presentation of the data based on qualitative analysis on classification of Maqasid al-Shariah from Islamic classic literatures. The result is the abortion is only allowed at the level of hajiyyat that to prevent thalassemia before the fetus is alive on 120 days of gestation. At elapse of 120 days of gestation, the life of the fetus is protected at the level of daruriyyat and the concern shift from prevention to treatment, termining factors in critical decision-making process in medical cases.