The invention provides a window type embedded fresh air system. The system includes a system shell; the system shell is installed on the upper or lower sides of a window; one side of the system shellis provided with an outdoor air inlet, and the other side of the system shell is provided with an indoor air outlet; the outdoor air inlet and the indoor air outlet are in interlaced arrangement; a fan is arranged between the outdoor air inlet and the indoor air outlet; the fan can guarantee the positive air pressure in a room; the system shell on one side of the fan is provided with a control chamber; the control chamber is provided with a power supply, an electric control and a sensing system; and the outdoor air inlet is provided with a pm 2.5 filtering device. The system can be embedded into the upper and lower parts of the window without limiting the width of the window; the system is simple in installation; introduced outdoor fresh air can enter the room after the filtering through the system, so that pm 2.5 can be prevented from entering the room; indoor oxygen content can be increased through the introduced outdoor fresh air; the fan 2 can guarantee the room to be positive airpressure, so that small noise and low power consumption can be achieved; and good indoor air can be guaranteed without opening the window after the system is installed to use.