[Objective/significance] The content of media communication is a reproduction and representation of users' cultural attitudes. The real emotions of netizens are expressed, gathered and spread through the media, forming a unique online emotion. The popularity of online emotions is often affected by cultural patterns in intercultural context, resulting differences in expression. Understanding the mechanism that causes differences and understanding the final results, we can effectively identify and guide the development of online emotions, and avoid cultural misunderstanding and cultural conflicts, which has important practical significance. [Methods/Procedure] Based on the Emotion Appraisal Theory, this paper analyzes the online emotions of China, Japan and South Korea in recent years, and makes an analogical and quantitative analysis of its valence effect.[Findings/Conclusion]It is found that netizens' emotions tend to be negative for the violent plots in online cartoons, but the netizens from different countries show subtle differences due to the influence of emotional concerns and cultural background. Around the influence of the cultural mode in the works, the online emotion shows the characteristics of high arousal. On this basis, the spread of emotion in the webtoons reveals the multi-level cultural factors in the emotional expression. Therefore, the society should pay attention to the guiding function of positive emotions, and improve the correct communication effect.