A method and a system for implementing hard handovers between access networks are provided, and the method includes: the access network on the target side obtaining the loop round trip delay of the pilot of the access network on the target side, and setting a center of a searching window of the pilot of the access network on the target side according to the obtained loop round trip delay of the pilot of the access network on the target side, so as to carry out the hard handovers between the access network on the source side and the access network on the target side. With the invention, the hard handovers between access networks could be implemented successfully.