【Objective】To measure the orbital fat fraction（FF）of Graves ophthalmopathy（GO）patients and normal individuals with MR Water- fat separation（Dixon） technology ，and to explore the value of orbit MR quantitative fat analysis in diagnosis and treatment for GO patients.【Methods】Forty GO patients and 20 normal individuals who underwent orbital MR imaging were analyzed prospectively from February 2017 to February 2019 in the First Affiliated Hospital of Sun Yat- sen University. All participants received bilateral orbital MR examination with oblique coronary FSE T2- weighted imaging combined with two-point Dixon technique，and then the signal intensity values of ipsilateral extraocular muscles and lacrimal glands on water and fat phase images were measured to calculate FF. The differences of mean FF between the two groups were evaluated，and the correlation between FF of GO and TRAb，CAS score，and the course of GO were conducted by Spearman rank correlation analysis. 【Results】 The median FF of extraocular muscles in GO patients was higher than that of normal individuals，and the result showed a statistically significant difference（P < 0.05）， while the FF of lacrimal glands in the two groups showed no statistical difference. The FF of extraocular muscles in the GO group were correlated with TRAb，CAS score and the course of GO（P < 0.05），especially the course was more correlative.【Conclusions】The fat content of extraocular muscles in GO patients were higher than that of normal individuals ，and there was a positive correlation in the fat content among TRAb，CAS score and the course of GO，suggesting that MR fat quantitative analysis may provide a new reference indexes for the evaluation of clinical staging ，curative effect assessment in GO patients.