This paper aims to analyze the phenomenon of the code-switching and code-mixing reflected in the dialogue of group chats between Korean-Chinese people on mobile messenger. In recent years, Korean-Chinese have been living in a language environment of ``two written languages and three spoken languages``. Korean-Chinese communicate in Chinese and Korean as written languages, but in Chinese, Joseoneo and Korean as spoken languages. The group chatting of Korean-Chinese reflects the characteristic(s) of code-switching and code-mixing occurring in the language environment. This paper attempts to analyze the communication strategy through three elements - economic feasibility, relationship and normativity - from the point of view of pragmatics. This paper attempts to forecast the future of Joseoneo through analysis of the phenomenon of code-switching and code-mixing, and provide the most appropriate solutions.