Aims: To investigate the functional connectivity (FC) in nonacute sciatica and the neuronal correlation of acupuncture analgesia. Methods: A prospective study employing resting-state functional magnetic resonance imaging was conducted. Twelve sciatica patients were enrolled to receive six or 18 acupoints of acupuncture treatment twice a week for 4 weeks. Regional homogeneity (ReHo) and seed-based FC were performed. Results: Regional homogeneity analysis demonstrated a greater alteration in the right posterior cingulate cortex (PCC) during the pre-acupuncture phase than during the postacupuncture phase. Compared to that of healthy controls, the PCC-seeded FC (default mode network, DMN) of sciatica patients exhibited hyperconnectivity of PCC-FC with the PCC-bilateral insula, cerebellum, inferior parietal lobule, right medial prefrontal cortex, and dorsal anterior cingulate cortex during the pre-acupuncture phase as well as hypoconnectivity of PCC-FC with the right cerebellum, left precuneus, and left dorsal medial prefrontal cortex during the postacupuncture phase. Correlation analysis between PCC-seeded FC and behavior measurements revealed a positive association with the duration of sciatica in the right inferior parietal lobule prior to acupuncture treatment. Conclusions: Acupuncture in chronic sciatica patients is associated with normalized DMN activity and modulation of descending pain processing. The changes in the subclinical endophenotype of brain FC after acupuncture treatment may provide clues for understanding the mechanism of acupuncture-mediated analgesia in chronic pain.