The study of gas-solid flow of slender particles is one of the key issues of that of gas-solid two-phase flow. The modeling of motion and force of slender particles in a flow field and the establishment of two-way coupling relation between slender particles and flow field are one of the key researches of gas-solid flow of slender particles. In this paper

on the basis of earlier created models of motion and force of slender particles based on rigid dynamics

in combination with the coupling correlation between Lagrangian time scales and κ-ε model

and with the modified inter-slender particle collision model

a high Reynolds number semi-dense or dense gas-solid multi-way coupling model of slender particles was established. A gas-solid two-phase flow field of slender particles in a riser was simulated using this model. It was shown that there is an evident randomness on the residence positions of slender particles in a riser at different time. The residence of slender particles resulted in the evident decline of pressure and velocity of local flow field. It was also found that there was an evident orientation selectivity of slender particles in the process of fluidization.