Abstract: Stray current prevention of metro depot has always been a weak part in metro projects. At present, a lot of depots reduce stray current by setting insulation rail gap and unilateral connecting device to isolate the current. By analyzing problems such as setup of insulation rail gap before buffer stop on electrified track, wheel lathe garage equipment short\|circuit and unilateral\|conducting frame reverse conduction that are existing in current prevention measures, corresponding optimization solutions are proposed.