The four principles of bioethics advocated by Beauchamp and Childress in their co-authored book The Principles of Medical Ethics published in 1979 have emerged as the universally accepted norm of bioethics today. This paper intends applied these four principles on moral issues, e.g. suicide, euthanasia, abortion, in-vitro fertilization, surrogate motherhood and human cloning. From these bioethical points of view, we'll concern the value of life.