In CPS related embedded system design area, time predictability is becoming increasingly important. The system of time predictability can be divided into two level:the programming level based on the traditional RTOS or platform and the architecture level extended with time behavior. In this paper, based on the research between the predictable architecture and the predictable programming model, and a new programming model based on both PRET(PRecised Timed machine) was proposed. Finally an implementation based on this new model was exhibited, through this exhibition we can find that this new model had advantages to the Giotto model.