A method for controlling torque reduction of a hybrid electric vehicle including a motor and an engine as a power source includes: calculating a total request amount of torque reduction when a torque reduction is requested; calculating a driving torque contribution of the engine and a driving torque contribution of the motor when the engine is turned on; dividing the total request amount of torque reduction into an amount of engine torque reduction and an amount of motor torque reduction based on the driving torque contribution of the engine and the driving torque contribution of the motor; determining an engine torque command and a motor torque command according to the amount of engine torque reduction and the amount of motor torque reduction; and performing torque reduction according to the engine torque command and the motor torque command.