The present study explored preschoolers’ abilities to justify their moral emotion attribution and its relationship with children’s moral reasoning. The sample consisted of 77 6-year-old preschoolers. Data were collected through individual interview of moral reasoning tasks and questionnaire for parents. The study examined the relationship between moral cognition and moral emotion, the roles of contextual differences and individual moral reaction tendency on justification of emotion attributions, and the influence of parenting on preschoolers’ moral reasoning ability. There are three main findings: (1) In contrast to the moral judgment reasoning, variable traditionally used logical corresponding relationships between moral cognition and moral emotion were found when justification of moral emotion attribution was used as a cognitive variable; (2) The moral reasoning level of preschoolers’ justifications of emotion attributions was lower, but children’s responses differed by moral contexts, and there are positive. Relationships between moral emotions and the justifications within and across contexts; (3) If parents explained to the children gently and showed sadness upon children’s wrongdoing, children’s abilities to justify their moral emotion attribution were better. Based on these findings suggestions for future research and moral education were proposed.