A design of portable multi-channel video monitoring system based on universal data subscriber loop (UDSL) is proposed. Another monitoring terminal and operation interface belonging to the security personnel can be realized quickly and conveniently based on building monitoring system. And the terminal locations can be distributed in any room with telephone network in the buildings. This method can form a direct link via the telephone line without the need for operators to provide related services, which has a strong concealment and operability. By using miniaturization and integration technology, the mobile transportation and installation of the equipment can be achieved. Experimental results show that the design of the system is correct and reasonable, the video communication link is normal and it does not affect the monitoring performance of the original video monitoring system.