A method for transmitting downlink data from a BS in a wireless communication system is disclosed. The method comprises receiving a first request signal of the downlink data from a first UE at a first timing point; transmitting packet of the downlink data to the first UE by using a unicast scheme until a multicast preparation time period passes from the first timing point; receiving a second request signal of the downlink data from a second UE at a second timing point after the first timing point; transmitting packet of the downlink data to the second UE by using the unicast scheme until the multicast preparation time period passes from the second timing point; and transmitting packet of the downlink data to a multicast group, which includes the first UE and the second UE, by using a multicast scheme when the multicast preparation time period passes.