Is human nature evil? Where does evil come from? How can we get rid of evil? Contemporary New Confucian Tang Junyi (1909-1978) thinks that the question of evil does not receive enough attention in Confucian tradition, yet is worth further exploration. Tang’s ideas on the question of evil are grounded in the theories of scholars following Wang Yangming. This paper aims to elucidate their ideas in order to articulate a theory of evil in Confucianism. The three main ideas in this paper are: 1. Evil is the perverted manifestation of the goodness of human nature. By this discussion, the meaning of human nature, good and evil, li-yu, li-qi (especially yuanqi or primordial vital energy) will be revisited. 2. The emergence of evil is caused by the trapping of the mind. The inner connection of the cluster of concepts that are related to the question of evil, namely, si, zhi, zhuo, bi, pian, guo, e, yu, ni, xi, and wang will be clarified. The relationship between “knowledge” and “moral evil” will also be further discussed. 3. “Self-enlightenment in the moment” is the fundamental way to get rid of evil. I will explain, at different levels, how self-enlightenment in the moment could be the fundamental way to get rid of evil. By way of these three ideas, this paper aims to enrich our understanding of the theory of evil in Confucianism.