A sound control device in a vehicle and control method thereof may include obtaining energy per unit time of an audio signal corresponding to a preset low frequency band, calculating an allowable reference value based on a difference between a magnitude of energy per unit time of the audio signal and a magnitude of a preset maximum allowable input of a speaker, monitoring whether a magnitude of energy per unit time of a noise control signal for eliminating noise in the vehicle exceeds the allowable reference value, and adjusting a magnitude of the noise control signal when the magnitude of energy per unit time of the noise control signal exceeds the allowable reference value.