Real-time simulation of industrial equipment is a huge challenge nowadays.The high performance and fine-grained parallel computing provided by graphics processing units (GPUs) bring us closer to our goals.In this article,an industrial-scale rotating drum is simulated using simplified discrete element method (DEM) without consideration of the tangential components of contact force and particle rotation.A single GPU is used first to simulate a small model system with about 8000 particles in real-time,and the simulation is then scaled up to industrial scale using more than 200 GPUs in a 1D domain-decomposition parallelization mode.The overall speed is about 1/11 of the real-time.Optimization of the communication part of the parallel GPU codes can speed up the simulation further,indicating that such real-time simulations have not only methodological but also industrial implications in the near future.