Abstract: The fluctuating characteristics of flow pressure during pipeline transportation reflect the degree and energy of turbulence in pipe flow, fluctuation pressure has a significant impact on the safety and stable operation of pipeline transportation. In this study, the research team self-designed a physical model test device based on the research background of pipeline clean water coarse particle transportation. The hydraulic transport process of coarse sediment under different adverse slope angles of the pipeline is simulated by model experimental device.The fluctuation change of solid-liquid two-phase flow in pipeline transportation is obtained by analyzing the distribution diagram of instantaneous pressure and fluctuating pressure in the pipeline at different angles. The research team analyzes the change rules of the instantaneous pressure, time average pressure, amplitude distribution of fluctuating pressure and frequency spectrum characteristics of the pipe wall under different adverse slope angles. The experimental results of the physical experiment model device show that the fluctuation of solid-liquid two-phase flow in pipeline transportation increases significantly with the increase in the adverse slope angle of the pipeline, and the variance distribution diagram of the fluctuating pressure intuitively shows the trend of the fluctuating pressure volatility. When the inclination angle of the pipeline is increased, the time average pressure and instantaneous peak pressure of fluctuating pressure decrease with the increase in the inclination angle. With the increase in the inclination angle, the general trend of fluctuating peak pressure on the pipe wall increases gradually; the amplitude distribution law of fluctuating pressure conforms to the Gaussian distribution, and it is universally acknowledged that the Gaussian distribution function can be used to fit the amplitude distribution of fluctuating pressure. With the increase in the tilt angle, the amplitude of fluctuating pressure increases gradually relatively, and the shape of the probability density function of fluctuating pressure has gradually developed from “tall and thin” to “short and fat”. The dominant frequency of the power spectrum function of fluctuating pressure is mainly concentrated in the main frequency range of 25 Hz. As the inclination angle of the pipeline increases, the dominant frequency of fluctuating pressure gradually develops to a larger frequency, and the overall change trend of fluctuating pressure is small in general.