In his novel The Family Moskat, Isaac Bashevis Singer not only explores and discusses the ethical dilemma faced by Jewish community in the early 1900s, but highlights the core value of ethic in Jewish society as well. The literary text focuses on Jewish young man, Asa, who attempts to reconstruct the reasonable and secular ethics instead of his original traditional Jewish ethics, but loses his way in the confusion between the traditional and the new ethics with breaking ethical orders continually, ending up with his broken marriage and tragic destiny of death. Through the narration, Singer strengthens the power of ethic and warns people that any act of violating ethical orders and relations would be punished severely. This essay intends to focus on the ethical changes leading to Asa’s choices, analyzing his conflicting emotions and hesitating moral concerns under the struggle between the tradition and the newness from the perspective of ethical literary criticism. The paper decodes a set of ethical complexes and demonstrates Asa’s tragic fate as an epitome of the Jewish people who fail to reconstruct new ethical values in that period of time.