Abstract: The research on the multiphase flow characteristics of hydrate slurry is the key to implementing the risk prevention and control technology of hydrate slurry in deep-water oil and gas mixed transportation system. This paper established a geometric model based on the high-pressure hydrate slurry experimental loop. The model was used to carry out simulation research on the flow characteristics of gas-liquid-solid three-phase flow. The specific research is as follows: Firstly, the effects of factors such as slurry flow velocity, hydrate particle density, hydrate particle size, and hydrate volume fraction on the stratified smooth flow were specifically studied. Orthogonal test obtained particle size has the most influence on the particle concentration distribution. The slurry flow velocity is gradually increased based on stratified smooth flow. Various flow patterns were observed and their characteristics were analyzed. Secondly, increasing the slurry velocity to 2 m/s could achieve the slurry flow pattern of partial hydrate in the pipeline transition from stratified smooth flow to wavy flow. When the flow rate increases to 3 m/s, a violent wave forms throughout the entire loop. Based on wave flow, as the velocity increased to 4 m/s, and the flow pattern changed to slug flow. When the particle concentration was below 10%, the increase of the concentration would aggravate the slug flow trend; if the particle concentration was above 10%, the increase of the concentration would weaken the slug flow trend, the increase of particle density and liquid viscosity would weaken the tendency of slug flow. The relationship between the pressure drop gradients of several different flow patterns is: slug flow > wave flow > stratified smooth flow.