Abstract: Real-time garbage collection should collect unused memory and guarantee real-time tasks to meet their deadlines. Furthermore, system memory requirement should be considered. A hybrid garbage collection is proposed in this paper. Reference counting algorithm is used to collect acyclic garbage and timestamp algorithm is used to collect cyclic garbage. GC and real-time tasks are scheduled concurrently. The proposed GC not only collects all unused memory but also reduces memory requirement compared with hybrid GC based on mark-sweep algorithm. It fits for large-scale system.