The number of students with academic difficulties have not disappeared in school although they have taken advantages of education service. Educators and administrators have tried to improve their achievement level but have often failed. In this research, the arithmetic performance characteristics of students with academic difficulties is discovered for providing proper educational intervention to them through arithmetic error pattern analysis. There are two groups, students with academic difficulties and average achievement children. They are compared by descriptive analysis and HLM to find out the arithmetic performance characteristics of students with academic difficulties. According to the result of analysis, it is revealed that poor performance of students with academic difficulties in arithmetic performance comes from lack of recognizing basic number facts and understanding basic concept. Therefore, the result shows us what part teachers who instruct students with academic difficulties focus on. Key words : students with academic difficulties, arithmetic error analysis