Abstract: Objective: To address the engineering challenges faced by Shanghai Rail Transit Chongming Line rivercrossing interval, such as the long distance between the interval power lighting equipment, and the limited civil engineering conditions, a targeted analysis and study of interval power supply and distribution scheme is required.Method: A twostage voltage reduction power supply method of 35 kV/6 kV/0.4 kV is proposed, and key technical issues such as equipment model selection and layout, grounding device design, relay protection, and power monitoring data transmission for the interval substation are analyzed emphatically.Result and Conclusion: A design scheme for setting a 6 kV mediumvoltage network and a 6 kV/0.4 kV interval substation in the interval is proposed, key technical issues such as electrical main wiring, main equipment model selection, interval substation grounding device design, 6 kV system relay protection configuration, and data upload for substation comprehensive automation system are thoroughly studied. Results show that this scheme can effectively solve the power supply problem for the power lighting equipment in this superlong interval of Shanghai Rail Transit Chongming Line.