A method for mobile communication handover and a system and a base station thereof are disclosed in the embodiments of present invention, wherein the method includes steps: on the basis of first link which only bears DCH service and has already existed, adding a second link bearing DCH and E-DCH services and a third link bearing any service; making softer combining for the DCH service of the first link and the second link; in the case of failing to add the third link, informing radio network controller by carrying the DCH softer combining information and E-DCH service addition information which are not in a same diversity indication choice field in link addition failure message. The embodiment of present invention could enhance the successful ratio of communication handover, and maintain communication continuously.