The aim of this study is to quantitatively assess the resting-state brain activity in migraine patients during the headache-free phase with magnetoencephalography (MEG). A total of 25 migraine patients during the headache-free phase and 25 gender- and age-matched control patients were studied with a whole-head MEG system at eyes-closed resting-state. MEG data were analyzed in multifrequency range of 4-200Hz. In a regional cortex analysis, the spectral power of gamma oscillations in left frontal and left temporal regions was significantly increased in migraine patients as compared to controls (all p<0.001), but no significant difference was found between the two groups for the global channels. Analyses of source location showed that there were significant differences in the distribution of gamma oscillation between migraine subjects and controls (p<0.025). Migraine patients in resting-state had altered brain activities in spectral power value and source distribution that can be detected and analyzed by MEG. Abnormal brain activities in the left frontal and temporal regions may be involved in pain modulation and processing of migraine. These findings provide new insights into the possible mechanisms of migraine attacks.