To explore the migration distribution laws of the cleaning agent of solid powder in industrial ventilation pipelines, a gas-solid flow migration model based on dense discrete phase model (DDPM) was built. Influences of various material injection methods (injection and jetting methods), positions, and directions in the narrowing zone of pipelines based on the migration laws of particulate cleaning agents in the pipelines were analysed. Results demonstrate that under the top injection method in the narrowing zone, the particulate cleaning agent presents obvious flow characteristics along the pipeline walls and cleaning agent concentration distributes unevenly in the pipelines. After the injection method is changed to top jetting, particle concentration remains high at one end near the wall and low at the other end. After changing the mouth from the top of the narrowing zone to the middle section and changing the spraying direction from perpendicular to the mainstream direction to the horizontal, the particle concentration of the cleaning agent reaches uniform distribution near the mouth and at the pipeline ends. Particle concentration in the pipelines is improved significantly.