The inclined pipe is widely used as a downward particle-conveying structure. Bubbles accompanying with the descending particles always induce complex flow pattern and pipe vibration, which would shorten the service life of equipment. In this paper, the gas-solid interaction and fluid-vibration coupling were experimentally studied by analyzing dynamic pressure and displacement of an inclined pipe. The results showed that, with increased mass flow rate, there was a progressive gas-solid flow behavior in the inclined pipe due to the water-pouring phenomenon. With the generation and upward channeling flow of bubbles, the downward particle flow showed an unstable motion, causing pressure fluctuations and severe vibration of the pipe system. Downward behavior of particles in the inclined pipe were eventually divided into three flow patterns: (1) creeping stratified flow, (2) gas channeling flow, and (3) dense phase fluidization flow. This work can provide theoretical basis for the design and operation of inclined pipe. (c) 2021 Published by Elsevier B.V.