in which HIL simulation is performed at the device driver level, supporting a specific GPU only. For design space exploration of CPU-GPU heterogeneous architecture, it is necessary to support various GPUs. To this end, we propose a GPU-HIL simulation technique that integrates a real GPU at the OpenGL ES API level, aiming to make a good compromise between speed and timing accuracy. Technical challenges and proposed solutions are presented in detail. Using three OpenGL ES Android benchmarks, preliminary experiments show some use cases of the proposed simulation framework for design space exploration and API-level dynamic behavior monitoring.