This article presents three perspectives in analyzing the influence of legal moralism on criminalization. First, is morally wrong conduct sufficient to justify criminalization? Second,is morally wrong conduct necessary to justify criminalization? Finally,is morally wrong conduct able to establish an affirmative reason for criminalization? If Legal Moralism is to be a persuasive theory of criminalization,it must clear the following three hurdles: 1) It must offer the conditions of criminalization other than moral wrongfulness, 2) It must offer a reason that any crime is morally wrong，3) It must clarify the concrete content of moral wrongfulness that can be an affirmative reason for criminalization.To the best of my knowledge, no theory of legal moralism has satisfied all three tests. However, any theory of criminalization faces similar dilemmas. It must offer a systematic explanation of the conditions of criminalization, consider whether a common principle exists, and provide positive reasons for criminalization.