A well-designed learning environment is crucial for enhancing both the physical and mental health of students, which in turn improves their learning outcomes. However, many classrooms in China, particularly in rural areas, were constructed and designed several decades ago, so it is essential to redesign these learning spaces to align with the requirements of 21st Century education. This study aims to develop the stimulation, individuality, and naturalness (SIN) theoretical framework for identifying the learning environment of current classroom by examining the full range of sensory effects experienced by individuals. This study conducted qualitative interviews with 72 students and 18 class teachers to explore major issues with their existing learning spaces in four primary schools in Shandong Province of China. The results show that high temperatures and poor air quality are frequently raised by respondents, which directly impact students’ learning experience. This finding confirms naturalness likely underpins human comfort. Teachers and students felt that the classroom should be improved from the aspects of crowded space, imperceptible decoration, congestion and monotonous layouts. The study emphasised the important factors that designers and policymakers should consider to promote a comfortable, efficient, and healthy learning environment.