Cognitive inhibition had been proven to play a critical role in solving word problem, especially when it comes to misleading information. The purpose of this study is to identify cognitive inhibition process in solving arithmetic word problem for middle school students who had reflective and impulsive cognitive style. We investigated whether students with different cognitive style will have different inhibition cognitive processes in solving word problem. The students  administered: i) MFFT and mathematic performance test to find out their cognitive style and their performance in math, ii) arithmetic word problem contains misleading information, and iii) interview. We found that student with reflective cognitive style inhibited confusing information and tend to choose and selected easy-to-use information, as for students with impulsive cognitive style kept questioning themselves and inhibited solution that comes in mind, so they believed that the problem couldn’t be solved if all the information weren’t used in solution.