Abstract: The influence of different grounding modes of high-voltage cable metal sheath on the power supply of traction substation was studied, through the study of three mainstream grounding modes of high-voltage cable metal sheath including direct-direct, direct-protection and cross interconnection, the advantages, disadvantages and application scope of various grounding modes were analyzed. The particularity of the load of traction substation was comprehensively analyzed, the influence of three mainstream high-voltage cable metal sheath grounding modes on the high-voltage cable connecting traction substation was studied, and the pricipal that direct-protection grounding is the most suitable grounding method for the high-voltage cable metal sheath connecting traction substation was determined. The research results can be given to avoid the fault of high-voltage cable connecting traction substation caused by wrong grounding mode.