Many thanks samc and rcojunos. I reboot the system can solve the problem.
First i connect with rj-45 serial port login the system.
Next backup the configuration and software image with following command:
save config from flash to [tftp <address> | pcmcia | slot1} <filename>
save software from flash to [tftp <address> | pcmcia | slot1] <filename>
Than, type 'reset' and 'y' to reboot the system.
Final, I can access the webUI.
Thanks,
Lou