Postherpetic Neuralgia (PHN) is a kind of chronic refractory neuropathic pain, yet there is a lack of knowledge regarding underlying brain activity. To further investigate brain activity changes in patients with PHN, we used amplitude of low frequency fluctuation (ALFF) analysis of resting-state fMRI to observe basal brain activity in those patients. Resting-state fMRI acquired in 8 PHN patients as well as in 8 age- and sex-matched normal controls was compared. Voxel-based multiple regression analysis was performed by SPM8 with voxel-wised ALFF as dependent variable, VAS score and pain duration as a covariate of interest. Comparing with healthy controls, PHN showed significant ALFF increases associated with VAS score in right cerebellum posterior lobe, dorsolateral prefrontal cortex (BA11/46/47), right parietal lobe (BA40) and right lingual gyrus(BA17/18/19); significant ALFF decreases associated with VAS score in right middle temporal gyrus(BA21), left lingual gyrus(BA17/18), right cerebellum anterior lobe, left posterior cingulate(BA30/19) and right precentral gyrus(BA3/4/6); significant ALFF increases associated with pain duration in right cerebellum posterior lobe, right middle frontal gyrus, dorsolateral prefrontal cortex(BA9/10/11/47), left superior temporal gyrus (BA38), right parietal lobe and right lingual gyrus (BA17/18/19); significant ALFF decreases associated with pain duration in left parahippocampa Gyrus (BA28), right cerebellum anterior lobe, left cingulate gyrus (BA24), right superior temporal gyrus (BA13), left precentral gyrus and right inferior parietal lobule (BA39/40). The results suggested that the brain areas involved in emotion, attention of pain played an important role in the modulation of PHN.