The use of semiotic resources in developing abilities and skills in physics problems is very important. PIMCA learning model (Presentation, Idea Mapping, Conceptualization and Formative Assessment) introduced and developed by Cosmas Poluakan is the focus of this research. The purpose of this study was to analyze student difficulties on learning the refraction using the PIMCA model based on multi-representation (MR). The type of research used experimental research with one group pretest-posttest design. The research was conducted in the Department of Physics, Manado State University, with 23 students as respondents. The test instrument used for this research has been validated. After processing and analyzing the data, the pretest average score was 15.9 and the posttest average score was 60.2. These results indicate that even though there is an increase in the average proportion of mastery of the refraction of light concept, generally students still have difficulty drawing the angle of incidence, direction of refraction and the position of refraction for the arrangement of 2 mediums. The results of this research recommend that in order to understand the concept of refraction, the use of the PIMCA model needs to provide more practice questions.