Abstract: In this paper, a solution is proposed to quickly and effectively solve the problems of communication signal coverage of the interphone in the severely shielded environment formed by the tall buildings. The relay station is integrated with the portable accumulator to act as the mobile wireless relay subsystem, so as to realize the signal amplification of the interphone and ultimately achieve the goal of extending coverage range. The experimental result shows that when transfer station is accessed in B-1 floor, the results simulated by using ray tracing are in good agreement with the test data except few points, therefore, the communication distance of the interphone can be effectively extended to B-2 and B-3 floor by the two-stage cascaded wireless relay subsystem. The test result show that the goal of convenient application of rapid deployment can be achieved without the help of the on-site engineering construction, thus can provid an effective guarantee for the power maintenance and communication.