Objective To observe the clinical efficacy of electroacupuncture at Zusanli (ST36) and Diji (SP8) in easing pain after Caesarean section (C-section) and the safety of the treatment. Method Sixty patients going to receive lower-uterine-segment C-section were enrolled and randomized into two groups. The control group was intervened by patient-controlled intravenous analgesia (PCIA) with Sufentanil after the surgery, while the treatment group was intervened by 30-minute electroacupuncture (EA) after the surgery. The contents of blood β-endorphin (β-EP), 5-hydroxytryptamine (5-HT) and prostaglandin E2 (PGE2) were evaluated at several time points: prior to EA (T1), 2 h after the surgery (T2), 12 h after the surgery (T3), 24 h after the surgery (T4) and 48 h after the surgery (T5). Visual Analogue Scale (VAS) was adopted to measure pain intensity at T2, T3, T4 and T5. The therapeutic efficacy, safety level and adverse reactions were recorded at each time point. Result The VAS score was significantly lower in the treatment group than in the control group at T2, T3 and T4 (P<0.05). The content of plasma β-EP in the treatment group was significantly increased compared to that in the control group at T3, T4, and T5 (P<0.05). The contents of plasma 5-HT and PGE2 in the treatment group were significantly decreased compared to those in the control group (P<0.05). In the control group, the contents of 5-HT and PGE2 at T2, T3, and T4 were significantly higher than those at T1 (P<0.05); in the treatment group, the content of β-EP at T3, T4 and T5 wassignificantly higher than that at T1 (P<0.05). There were no significant intra-group differences in comparing the contents of PGE2 and 5-HT at each time point in the treatment group (P>0.05). Regarding the efficacy evaluation, the excellent rate was 86.7% in the treatment group 2 h after the surgery, significantly higher than 60.0% in the control group (P<0.05). The security level in the treatment group was markedly higher than that in the control group (P< 0.05). Conclusion EA can provide a safe and effective post-operation analgesia for C-section, and the possible mechanism is that EA at Zusanli and Diji increases the secretion of β-EP and inhibits the release of inflammatory mediators 5-HT and PGE2.