Disclosed herein is a battery discharge preventing system for a hybrid vehicle including a high voltage battery that drives a motor of the vehicle, a low voltage battery that supplies power to a black box, a first voltage sensor that measures a voltage level of the low voltage battery, a converter that charges the low voltage battery using the high voltage battery, a first relay that selectively regulates a current path between the high voltage battery and the converter, and a control unit that controls the first relay according to a measurement value of the first voltage sensor.