In this paper, an active type variable intake system is proposed, which improves both engine power and NVH performance. The proposed system uses a magnet valve to control the air path to the engine intake manifold.While other types of variable intake system such as vacuum actuator type or DC motor type need an ECU to control the valve, the proposed system only uses force equilibrium between magnetic force and vacuum pressure, resulting in weight and cost reduction.The system is composed of dual duct (duct A, duct B) and a magnet valve. In low RPM region, the magnet valve is closed and only duct A is used to supply air into the engine. In high RPM region the valve opens up and maximizes the amount of the air that goes into the engine intake manifold. The result is that the output power of the engine is maximized in high RPM region, as well as the NVH performance is improved in low RPM region.