Based on CFD unsteady simulation, the airflow velocity field and droplet deposition model of the fixedpipe cold fogging system in greenhouse were established, and the airflow velocity and droplet deposition characteristics of the fogging system under different operating parameters were analyzed. At the same time, the experimental verification of the droplet deposition characteristics was implemented. Results showed that the fogging system formed vortex flows in greenhouse, which was beneficial to the floating, dispersion and deposition of droplets. The optimal operating parameter of the system was 0.3MPa with air pressure and 0.05MPa with hydraulic pressure. The maximum deposition amount of droplets directly below the nozzle and between the nozzles was distributed in the area of 1m in front of the nozzle spray direction (sampling point 5), decreasing along the nozzle spray direction. The amount of ground droplets deposited directly below the nozzle was lower than that in the middle area, while at the height of 40cm, 60cm and 80cm, the corresponding amount of droplet deposition directly below the nozzle was higher than that in the middle area. The droplets in the area directly below were mainly deposited in the height range of 60~80cm, and the droplets in the middle area were mainly distributed in the height area of 40cm and 80cm. The correlation coefficients of the simulated and measured droplet deposition amount at different heights under different operating parameters were ranged from 0.990 to 0.924. The relative error range between the simulated and measured droplet deposition amount was 0.008~0.374, indicating that the CFD simulation can accurately predict the airflow velocity field and droplet deposition characteristics of the fogging system, and guide its operating parameters optimization. 