The invention provides an improved launch vehicle electrical system electricity leakage test result calculation method, and relates to the field of launch vehicle electrical systems. The calculation method particularly comprises the following steps that 1, power is supplied by a ground power supply, and system electricity leakage test results are calculated, wherein a negative busbar electricity leakage test and a positive busbar electricity leakage test are conducted to obtain calculation formulas of a ground power supply voltage M respectively, the two calculation formulas are simultaneous, and an electricity leakage resistance value Rx and an electricity leakage resistance value Ry are obtained through calculation; 2, power is supplied by batteries on the vehicle, and system electricity leakage test results are calculated, wherein a negative busbar electricity leakage test and a positive busbar electricity leakage test are conducted to obtain calculation formulas of a ground power supply voltage M and a vehicle-mounted power supply voltage respectively, the two calculation formulas are simultaneous, and an electricity leakage resistance value Rx and an electricity leakage resistance value Ry are obtained through calculation. According to the method, the resistance values obtained under the double-end electricity leakage condition can be precisely calculated on the condition that double-end electricity leakage occurs on a system power supply busbar, and the problem that in an existing electricity leakage test method, the electricity leakage resistance cannot be precisely tested under the double-end electricity leakage condition.