Using a structural priming paradigm, the details of sentence production model have been investigated substantially, specifically the processes in grammatical encoding level. Many studies provide evidence that the function assignment stage and the constituent assembly stage are processed separately in grammatical encoding. However, it is less known whether these two stages interact with each other during the processes, and if so, how the processes are executed. In this study, we report three structural priming experiments in Japanese, in which function assignment and word order were manipulated independently and simultaneously in order to examine the processes at two stages directly. Our results revealed that priming effects patterns were different depending on whether the effects occur at function assignment stage or at constituent assembly stage. Based on the current findings, implications for the recent models of sentence production are discussed, from the perspective of the grammatical function assignment and word order determination.