the present invention provides a method of controlling wireless lan medium access using pseudo - time division multiplexing to improve the quality of service of the wlan . the method includes the first step of a mobile terminal acquiring qos information , which relates to a voice frame to be transmitted , from an upper layer ; the second step of the mt exchanging a frame , including the qos information , with the ap and being allocated qos slot information by the ap ; the third step of dividing an rf link section between the mt and the ap by the creation period of the voice frame ; and the fourth step of transmitting the voice frame in the creation period of the voice frame using the allocated qslot information .