System and method for terminal to obtain P-CSCF address

The invention relates to a system and a method for terminal acquisition of the P-CSCF address; wherein, the system comprises a terminal, a foreign agent accessed in the business network, an AAA server and a home agent connected with the business network, and a DHCP server of the dynamic host; wherein, a DHCP agent module or a DHCP relay module is arranged in the home agent of the system to achieve the DHCP agent function or the DHCP relay function; the process terminal of the home agent acquires the P-CSCF address information by the DHCP message of the dynamic host transmitted by the reverse tunnel, and feedback the P-CSCF address information to the terminal. The invention has the advantages of enabling the terminal to acquire the P-CSCF address, and further being connected in the P-CSCF by the WiMAX network, then in the IMS network to enjoy the IMS business.