The development of classical mechanics to quantum mechanics not only represents the progress of natural science, but also had a profound impaction in philosophy and social sciences field, at the same time it had changed people"s weltanschauung, and made peoples’ understanding of causality experienced from determinism transition to the non-determinism. With the tendency of non-determinism in philosophy field, this tendency has also appeared in the field of law especially in the field of personal tort law, and this tendency has found a specific approach in theory and practice: the doctrine of chance losing in the field of medical tort.