This study is about educating people to understand mutual cultures with respect to the seasonal customs from three countries, and seeks to propose a method of cross-cultural education through the analysis of the three national holidays: Lunar New Year’s Day, Thanksgiving Day, and Dano festival. The reason for selecting China and Vietnam lies in the fact that the most number of people who get married with Koreans come from them. In the second chapter, the contention is made for the necessity of the education of cross-cultural understanding and the importance of practical use of seasonal customs. The third chapter examines Lunar New Year’s Day, Thanksgiving Day, and Dano festival of three countries respectively. In the fourth chapter, the three national holidays are analyzed and their characteristics are investigated under categories: aspect of seasonal customs, rituals, meaning, food, game, custom, etc. The fifth chapter discusses educational factors of cross-cultural understanding in multicultural families and seeks to propose a educational method using the seasonal customs. The importance of this study lies in the fact that we have to broaden the scope of cross-cultural understanding through acknowledgement and respect for the difference and diversity in multicultural families, and think of them as one. Some limitations apply to this study in the sense that the study does not meet the demand of exquisite research in folklore area. However, the significance of this study lies in the fact that it can be utilized as educational material for the purpose of the safe settlement of multicultural families and ensuring the authenticity of social integration.