Abstract: As a new grain storage structure, the double-story squat silo (DSSS) ensures the quality of grain storage and offers the advantages of land saving, energy saving and carbon reduction, etc. In this paper, a discrete element approach was used and a numerical analysis model for the center discharge of DSSS was constructed. Research objects of soybean, corn, rice and wheat were used to investigate the effect of different storage particles on the dynamic pressure of discharging at the center of DSSS, and the grey relational analysis method was also used to investigate the influencing factors of the dynamic pressure of the central discharge. The results firstly showed that wheat and rice present a funnel-shaped flow when discharging, and the amplitude of the discharging dynamic pressure oscillation is smaller. The unloading of soybean and corn showed an overall flow trend, and the discharging dynamic pressure show a trend of decreasing in continuous oscillation. Secondly, the particle velocity above the discharging port of rice and wheat was greater than the particle velocity on both sides, and the particle velocity distribution on both sides of the discharging port showed an obvious vertical stratification phenomenon, with each layer showing a gradual increase in particle velocity from top to bottom, while the distribution of particle velocity of soybean and maize showed a more irregular distribution. Thirdly, It was concluded that during the discharging process of DSSS, the dynamic pressure was greatly correlated with the rolling friction coefficient of the particle, the rolling friction coefficient between the silo body and the particle, the static friction coefficient of the particle, the correlation values were all above 0.8. This paper provides a theoretical guidance and technical support for the structural analysis of DSSS, which has important engineering application value and helps to promote the application of DSSS.