A method for moving MS in the manner of the least packet loss can be divided into two steps. In the first step, when the MS is still connected to the source CN node and is running the effective loads, the MS prepares the routing information pointing at the target CN node. In the second step, the connection between the source CN node and the RAN node is released, the MS ID, the context data and the mobile information are transmitted to the target CN node. Then, a new connection between the target CN node and the RAN node is established. The step is completed synchronously and rapidly to minimize the packet loss. When establishing a new connection, the routing information transmitted to the MS before is used so that a new CN node is pointed at.