In this paper, we reviewed studies that investigated the development of the regulation of emotional expression during childhood in light of the current understanding and implementation of this process in children, and we discussed the mechanism of its developmental trajectory. To understand the process, socialization by parents, understanding of the mind, and daily communication experiences may be important. To implement this process, socialization and the development of the ability of inhibitory control and emotional knowledge may also be important. We suggest a developmental mechanism whereby the understanding and the implementation of the regulation of emotional expression may not be isolated factors but instead influence each other. We concluded the paper by discussing the future direction of the study of the regulation of emotional expression.