Abstract: The offshore gas-slurry multiphase pipeline is a kind of new technology for energy transportation, which would help solving the problem of hydrate plugging in multiphase pipelines in deep seas. Studying the flow properties of NGH slurry is an important foundation of industrial application of this technology and the microstructure of the slurry is an essential factor to determine the flow properties. Several kinds of mechanism explanations of the aggregation of hydrate particles and two kinds of experimental methods are presented in this paper.