The present disclosure relates to an apparatus for detecting malfunction of a relay, which includes a temperature determination unit configured to determine whether or not a relay resistor is overheated based on a resistance temperature of the relay resistor being connected to a relay; a charging voltage determination unit configured to determine whether or not a variation value of a charging voltage of a direct current (DC) link capacitor according to an operation start of an inverter system exceeds a reference variation value; and a relay malfunction determination unit configured to determine whether or not the relay is malfunctioned based on one or more the determination results whether or not the relay resistor is overheated and whether or not the variation value exceeds the reference variation value.