Abstract: The mechanism of interference structures caused by broadband continuous-spectrum noise radiated by a high-speed vertical moving source is analyzed based on ray theory. The path equations of interference fringes are derived and the factors affecting the interference characteristics are discussed. Finally, the characteristics and laws of interference structures are revealed. Theoretical and simulation results indicate that the interference periods are inversely proportional to the delay differences of multipath signals. The observability of interference fringes can be improved by decreasing the receiving depth or increasing the receiving range. Additionally, randomly undulatory sea surface can cause breakpoints of the interference fringes and reduce the observability. Real data results have confirmed that the interference structures are primarily composed of directed-bottom-reflected wave. Moreover, the interference period increases as the horizontal range increases. The research has potential application prospects for target motion analysis and environment parameter inversion.