A wireless electric power receiving device and a wireless electric power transmission system. The wireless electric power receiving device (106) is coupled to a wireless electric power transmitting device (102). The wireless electric power receiving device comprises a receiving coil (108), a power supply circuit (110) and an alarm unit (114). When the receiving coil is coupled, a coupled voltage is generated and outputted. The power supply circuit comprises a first receiving terminal (118) coupled to the receiving coil, and compares the coupled voltage with a preset operation voltage range to generate and output a control signal when the coupled voltage is beyond the preset operation voltage range. The alarm unit is coupled electrically to the power supply circuit so as to receive the control signal from the power supply circuit and output an alarm signal according to the control signal. The device can prevent a user from misusing a household electrical appliance in case of a deficient voltage.