A method for a wireless access point for operating WLAN cards in a power-saving mode in a wireless communication system. The method includes: (a) storing data to be transmitted to the WLAN cards in the wireless access point of the wireless communication system; (b) receiving aging times of the WLAN cards according to durations of the WLAN cards waiting for receiving the data stored in the wireless access point; (c) when the aging times are smaller than a default, comparing unit-data-transmission amounts of the WLAN cards with the data stored in the wireless access point corresponding to the WLAN cards; and (d) when all the data stored in the wireless access point corresponding to the WLAN cards are less than the unit-data-transmission amounts of the WLAN cards, sequentially transmitting the data stored in the wireless access point corresponding to the WLAN cards according to a WLAN-card adding rule.