An information processing method, performed by a user equipment having a single registration mode, comprising: receiving assistance information from a first network; initiating an attaching or initial registration procedure according to the assistance information received from the first network when the UE is moving between the first network and a second network, the first and second networks utilizing different access technologies, wherein the first network is a 5G network and the second network is a LTE network, or the first network is a LTE network and the second network is a 5G network; the method is characterized in that, the step of initiating an attaching or initial registration procedure according to the assistance information received from the first network when the UE is moving between the first network and a second network comprises: determining that the single registration mode cannot be supported by the first network according to the assistance information received from the first network; initiating the attaching or initial registration procedure when accessing the second network; wherein the assistance information comprises: neighborhood measurement information; the step of determining that the single registration mode cannot be supported by the first network according to the assistance information received from the first network comprises: determining that the single registration mode cannot be supported by the first network, if the neighborhood measurement information does not comprise information about any cell of the access technology which the second network utilizes. receiving assistance information from a first network; initiating an attaching or initial registration procedure according to the assistance information received from the first network when the UE is moving between the first network and a second network, the first and second networks utilizing different access technologies, wherein the first network is a 5G network and the second network is a LTE network, or the first network is a LTE network and the second network is a 5G network; the method is characterized in that, the step of initiating an attaching or initial registration procedure according to the assistance information received from the first network when the UE is moving between the first network and a second network comprises: determining that the single registration mode cannot be supported by the first network according to the assistance information received from the first network; initiating the attaching or initial registration procedure when accessing the second network; wherein the assistance information comprises: neighborhood measurement information; the step of determining that the single registration mode cannot be supported by the first network according to the assistance information received from the first network comprises: determining that the single registration mode cannot be supported by the first network, if the neighborhood measurement information does not comprise information about any cell of the access technology which the second network utilizes. determining that the single registration mode cannot be supported by the first network according to the assistance information received from the first network; initiating the attaching or initial registration procedure when accessing the second network; wherein the assistance information comprises: neighborhood measurement information; the step of determining that the single registration mode cannot be supported by the first network according to the assistance information received from the first network comprises: determining that the single registration mode cannot be supported by the first network, if the neighborhood measurement information does not comprise information about any cell of the access technology which the second network utilizes.