Abstract：Using a longitudinal design, 60 children from the age of 4 to 6 were studied on the development of understanding and use of emotional expression rules in four situations.The results of this study show that: (1) The level of knowledge is the highest in aversion situation, the development of social orientation goals is first fast and then slow, and more concealment strategies are used; Self directed goals develop rapidly in happy situations, and use calming and weakening strategies; In sad situations, a variety of strategies are used comprehensively. In angry situations, the knowledge level is the lowest, and weakening strategies are rarely used for self-protection. (2) Children’s knowledge of emotional expression rules and exaggeration strategies are growing rapidly. The development of emotional expression goals varies from situation to situation, the development of weakening strategies varies with gender, and there is no age difference in concealment and calming strategies. (3) It can well explain some previous disputes about gender differences.