The disclosure provides an exposure-based advertising system, which comprises a tag, a mobile device, and a server. The tag comprises a signal transmitter for sending a signal encoding an identifier, a power supply for supplying power to the signal transmitter, and a signage; wherein the signal transmitter and the power supply are adhered at least partially to the signage. The mobile device is configured to receiving the signal transmitted from the tag, decoding the signal into an identifier, and record data associated with the identifier. The server is configured to communicate with the mobile device for determining a reward according to the data associated with the identifier and releasing the reward to the mobile device. An exposure-based advertising method is also provided. The exposure-based advertising system and method of the present disclosure offers effective advertisement exposure, high consumer acceptance, and strong incentive to engage.