Abstract: A mobile station and a power saving method thereof for a wireless communication system are provided. The wireless communication system comprises a base station and the mobile station. The mobile station stays in a sleep mode. The mobile station comprises a buffer, a transceiver, and a processor. The buffer is configured to temporarily store an uplink data packet. The transceiver is configured to receive a downlink traffic indication message during at least one listening interval. The processor, electrically connected to the transceiver and the buffer, is configured to determine that the downlink traffic indication message carries a non-having downlink data packet information to make the buffer continue to temporarily store the uplink data packet so that the mobile station continuously stays in the sleep mode.