This study explores the epistemological beliefs of pre-service elementary teachers in Korean language education and their impact on performance assessment task planning. Grounded in the correlation between teachers’ beliefs and instructional approaches, the research aims to redefine Schommer’s (1990) epistemological dimensions in tasks designed by pre-service teachers. Data from 150 participants were analyzed quantitatively and qualitatively, revealing three belief-based clusters: Naive (24.7%), Mixed (51.3%), and Sophisticated (24.0%). Task planning patterns in all groups focus on individual perspective analysis and selfreflection. The Mixed group emphasizes related readings, exposing participants to various perspectives. In contrast, the Naive group employs diverse tasks in multiple sessions, emphasizing critical interpretation and real-life situations. The Sophisticated group chooses perspectives from given texts, relying on textbooks or worksheets. Understanding how these beliefs are shaped or regulated during the assessment task planning informs the intersection of educational philosophy and practical application, laying the groundwork for well-informed educational practices and a nuanced understanding of epistemological beliefs.