The embodiments of the present application relate to the technical field of wireless communications, and in particular, to a method, system and device for transmitting data, so as to solve the problems existing in the prior art that a multicast message cannot be sent due to FACH limitation in a UMTS system, and a relatively large influence will be brought to the current system information scheduling mechanism if multicast data is issued through system information in an LTE system. The method of the embodiments of the present application comprises: a wireless access network receiving data of at least one group of user equipment from a core network, and the wireless access network transmitting data of a corresponding group to the user equipment in the group through user plane shared resource transmission. Due to this mode of adopting a shared channel to bear multicast data, the current relatively limited FACH resource in a UMTS system is thereby released, and the adoption of a shared channel can enable transfer of multicast data more rapidly and promptly. An LTE adopts a user plane to transmit multicast data, avoiding influence on the system information.