With the growing demand of the host mobility, the problems of overloading of IP address semantics are becoming increasingly serious. People have figured out various ID/Locator split technologies to support host mobility. In fact, current network environment is still in mixed IPv4/IPv6 transition phase, but the existing technology for host mobility in this transition phase is not considered comprehensively. In this paper, we propose a novel method to support host mobility between IPv4 and IPv6 network, and give a detailed explanation through a new ID/Locator split architecture which called RANGI (Routing Architecture for the Next Generation Internet). There are two contributions in this method: First, it supports the host mobility in transition phase; second, it is like the host mobility means in IPv6, so it provides a good capacity of smooth transition from IPv4 to IPv6.