In recent years, short range wireless communications have been used more and more frequently in our life. But the electromagnetic fields waves also have some disadvantages. One of these disadvantages is health problems. Many studies shows the electromagnetic field waves using for communication may damage our health. And in most hospitals, they also have bans on the use of mobile phones and wide area networks because of Electromagnetic Interference. So in this paper, we studied the use of ultrasound for wireless communication in air, instead of using electromagnetic field wave. An Alternating-Direction Implicit Finite-Difference Time-Domain (ADI-FDTD) method is developed to simulate the ultrasonic wave communication system. The ADI-FDTD simulations make it possible to better understand the behavior of an ultrasonic signal. Experimental data is also presented to compare with simulation. The results show that such a system is feasible in principle for communications using ultrasound.