The invention discloses an airflow control device for an inlet manifold. The device comprises an inlet manifold body, and four air vents are arranged on the inlet manifold body. Through grooves for communicating a first air vent with a second air vent and a third air vent with a fourth air vent are arranged between the first air vent and the second air vent and between the third air vent with the fourth air vent. The device further comprises partition boards and turning boards which are arranged corresponding to the air vents. Each of the partition boards is provided with two lugs in a protruding mode, and communicated through holes are coaxially arranged in the lugs. A turning board is arranged between the lugs, the first air vent and the turning board in the second air vent are fixedly connected into a whole, and the third air vent and the turning board in the fourth air vent are fixedly connected into a whole. Drivers for driving the turning boards to rotate are further arranged on the inlet manifold body. By means of the airflow control device for the inlet manifold, opening angles of the turning boards can be guaranteed to be identical, and simultaneously, the size is small, the structure is simple, and the cost is low. The airflow control device is applicable to inlet manifolds of engines to guarantee the fuel mixing effect.