Nonlinear acoustics has been a topic of research in the last years. Driven by a wide range and a large number of highly relevant industrial and medical applications, this area has expanded enormously in the last few decades. Numerical modeling of medical ultrasound has advanced significantly in recent years. Numerous algorithms have been developed and applied to study different medical ultrasound applications. Numerical simulations of the nonlinear acoustic field are performed by using the Westervelt equation. In this paper, FDTD scheme to solve Westervelt equation is presented. The main objective of this study is to analyze the Westervelt equation and apply the Finite Difference Method to obtain numerical solutions and the behavior of nonlinear acoustic waves in different biological mediums and investigate the effects of nonlinear interactions. Nonlinear equation is applied using different biological media and transducer pressure of 1 kpa with the frequency of 1 MHz is considered as the range of study to analyze the interaction of wave and tissue. Our results show the importance of considering nonlinear interactions in understanding the behavior of sound waves in biological tissues.