The work aims to optimize the design of structural parameters of metering screw in packaging machine and improve the conveying efficiency of metering screw without changing its speed and outer diameter. The conveying capacity model of the screw was established and the movement velocity of particles in the metering screw was analyzed. The typical particle morphology was observed by electron microscope. Then, the particle morphology was constructed in discrete element simulation environment, and the measurement and conveying process of powdery materials was simulated. The primary structural parameters were obtained by comparing the conveying capacity of metering screw with different structural parameters. The optimal structural parameters of screw were obtained based on particle swarm optimization algorithm, and the conveying capacity of optimized metering screw was compared and verified by simulation method. The conveying speed of optimized metering screw for powdery materials was 358.79 mm/s, and the conveying efficiency increased by 7.44%. The conveying efficiency of metering screw for powdery materials is improved by optimizing structural parameters and combining simulation, which provides basic data reference for design and processing of metering screw in industrial enterprises.