This article aims to make a positive discourse analysis of the Diplomatic Discourse between North and South Korea towards Vietnam through the comparison of attitude resources. This article based on the analytical framework of appraisal theory, employs diplomatic reports related to Vietnam published by North and South Korea from 2017 to 2022 as corpus, by means of UAM Corpus Tool and AntConc, to analyse the topic setting of evaluation subjects in North and South Korea, the distribution characteristics of attitude resources and the differences of diplomatic positions and attitudes revealed by their resources. The results show that on the topic setting, South Korea often focus on political diplomacy, economic cooperation, social culture, health and medical care between “Korea-Vietnam”, “Korea-Mekong” and “Korea-ASEAN”, while North Korea pays more attention to the friendly and cooperative relations with the Socialist Republic of Vietnam and the Communist Party of Vietnam. In the use of attitude resources, both South Korea and North Korea display the convergence characteristics, namely affect resources > appreciation resources > judgment resources. However, there are differences in the distribution characteristics of specific subordinate classification resources. In Diplomatic Discourse, both North and South Korea tend to adopt positive attitude resources to maintain and develop friendly relations with Vietnam from the standpoint of each country.