© 2020 Elsevier B.V. In this study, two-dimensional large-scale simulation of polycrystalline equiaxed solidification is enabled by applying an active parameter tracking and multiple GPUs computation to the phase-field lattice Boltzmann model, which can simulate growth of multiple dendrites with solid motion, liquid flow, collision and coalescence of multiple solids, and subsequent grain growth. It was confirmed that the developed simulation method shows a reasonable parallel efficiency through scalability evaluations. By using the developed method, showering simulations are performed, in which solid nuclei generated at the top of the computational domain settle down with growth into equiaxed dendrite and deposit on the bottom of the computational domain. In the simulations, a massive number of dendrites, up to 350, is successfully treated.