The purpose of this study was to analyze students understanding profile about simple harmonic motion conceptual. The subject of this study were eleventh grade student of sciences class in Surakarta2 State Senior High School with 90 students whose registered as student in the 2018/2019 school year. Sampling in this study used random sampling technique. To analyze students understanding profile used instrument of two tier test with 20 item. Instrument consists two level, first level is multiple choice questions and the second level is open ended free response question which is the reason of student’s answer to the first level questions. The result of this study show that 12,9% of students understanding the concept of simple harmonic motion, 16% of students understand in part, 18,2% of students show misconception, 31,5% of students show specific misconception, and 16,5% of students didn’t understand the concept. The highest concept understand was in concept relation of velocity, angular velocity, displacement and acceleration in simple harmonic motion with 41,11%, and the lowest was in definition of simple harmonic motion with 0,74%.