Objectives: To assess the efficacy of electro-acupuncture (EA) relative to sham electro-acupuncture (sham EA) in treating chronic severe functional constipation (CSFC). Methods: A comprehensive search for relevant studies published between January 1, 1951 and May 14, 2020 was conducted in PubMed, the Cochrane Library, Chinese Biomedical Literature Database, Web of Science, and EMbase. Two investigators independently selected studies, extracted data, and assessed the quality of the included studies. The software Endnote X9 was used for screening articles, and the Review Manager 5.3 for analyzing data. Results: The meta-analyses involved 6 studies and 1457 individuals. The pooled results favored the EA group for the increase of complete spontaneous bowel movements (CSBMs) per week in the fourth week (MD = 0.80, P = 0.001) during treatment, and further improved in the eight weeks (MD = 1.25, P < 0.001). During the follow-up period, significant changes in CSBMs per week were seen in the experimental group (MD = 1.38, P = 0.008); the effect decreased in the twelfth week (MD = 0.87, P < 0.001). There was no significant difference in the Bristol stool scale score between the two groups in the fourth week (MD = 0.40, P = 0.08), but significant differences were observed in the eighth week (MD = 0.40, P = 0.03). A significant reduction in patient assessment of constipation quality of life (PAC-QOL) score were observed in the EA group during treatment (SMD = -0.83, P < 0.001). No serious adverse events were reported. Conclusions: EA had favorable effects on CSFC, and the longer the treatment duration was, the better was the effect, but the effect showed a certain period of validity. However, the results may be influenced by the clinical heterogeneity of acupuncture points, depth of needling, intensity, and frequency of EA.