Abstract: In face of the dilemma of the “tram problem”, there is room for discussion whether emergency avoidance can be applied to exonerate the crime. Based on the questioning of the general view that “the value of life is not measurable”, this paper proposes the relativity of the value of life and the application scope for life avoidance in autonomous driving. In the choice of justification for the implementation of emergency avoidance of life, pure utilitarianism and social solidarity obligations have unavoidable defects, and the practical scope of application is limited. The modified utilitarian theory recognizes the value status of “the supremacy of life” in a general sense, but there are differences in the worthiness of different life subjects under special circumstances, and life is allowed to be measured under certain constraints. Under the guidance of this theory, through the concrete analysis of the collision situation in different scenarios of autonomous driving, a series of operating rules are obtained for algorithm guidance in program design, and the purpose of preventing illegal behavior is realized after the automatic driving program design meets the constitutive elements of emergency avoidance.