Abstract-The system design and development of embedded software is under a lot of challenges. Model-based software systems are drawing more and more attentions. In our previous work we proposed a system level design language named SyncBlock and developed a toolset for the design of synchronous embedded system. Although our toolset is superior for building synchronous models, it is difficult to model the external environment of embedded system ideally, and does not support asynchronous modeling functionalities or the merging of heterogeneous models of computation. Ptolemy II is a well-known modeling platform which supports many well-defined heterogeneous models of computation. In this paper we propose a series of rules and mechanisms on model transformation from SyncBlock to the SR model of computation in Ptolemy II for heterogeneous model merging. Using our method, we can model and simulate synchronous embedded systems by SyncBlock, and then simulate the designed model further coupling with external environment modeled by other models of computation in Ptolemy II like Discrete Event Domain, and finally generate codes by the SyncBlock modeling tool. Through heterogeneous model merging by model transformation, we combine the advantages of the two modeling tools.