Abstract: The concept of fractions is a major challenge in elementary mathematics learning, and misconceptions can effectively reflect students’ grasp of this concept. To explore the cognitive characteristics of elementary students regarding fractional quantities, the study employed cognitive interviews to analyze misconceptions among 40 sixth-grade students from public schools in Hohhot. The results indicate that students generally exhibit a low level of understanding of fractional quantities, with three main types of misconceptions: weak awareness of fractions as quantities, insufficient numerical sensitivity, and a pronounced tendency toward operator concepts and division bias. Further analysis reveals that the formation of fractional quantity concepts follows a specific cognitive developmental pathway-progressing from relational concepts (involving two quantities) to abstract quantity concepts (involving one quantity), and finally evolving into numerical concepts (representing a single number).