The goal of embedded systems is to embed services into our daily life in a convenient and comfortable manner without intrusions. The graphical user interfaces (GUIs) of embedded softwares play an important role in reaching this goal. However, the rapid growth of various types of embedded devices and platforms, especially mobile devices, brings more challenges and constraints for GUI design in embedded software. Current approaches in building conventional software GUI result in iterative refinement after it was built, which is not acceptable for embedded software. In this study, a GUI simulation model is proposed to assist embedded software developers to generate GUI prototypes in early phase. The generated prototype can be used to confirm the usability requirement of customers and eliminate the further need of iterative GUI refinement. The simulation is based on evolutionary simulation rules which evolve according to the training data and design experience from existing popular GUI designs, which implies high adaptability and flexibility to the changing world with newly released embedded devices.