This paper presents a simulation of the in-cylinder flow field during the intake process of an engine equipped with a dual-rotating valve cylinder head assembly, which was designed and developed by the project team. Based on the dimensions of the original prototype, a three-dimensional numerical model was established. Using Starccm software, the simulation calculation of the intake process flow field of the engine was carried out, and the results showed that the intake state of the dual-rotating valve system was stable and the flow field had no severe disturbance, which was beneficial to the engine’s intake. This paper proposes a simulation calculation method for the rotating valve engine, which has a certain reference value for the research and development of the new type of valve train system and its adaptation to different engines.