The invention relates to an EMI (Electro-Magnetic Interference) filter of an electrodeless fluorescent lamp with an ultracrystalline filter coil CL+CL structure, which comprises an earth wire, a first common mode filter coil device and a second common mode filter coil device, wherein the first common mode filter device is provided with a first and a second filter coil section input interfaces, and a first and a second filter coil section output interfaces; the second common mode filter coil device is provided with a third and a fourth filter coil section input interfaces, and a third and a fourth filter coil section output interfaces; the first filter coil section input interface is connected with the earth wire through a Y capacitor, the second filter coil section input port is connectedwith the earth wire through the Y capacitor, the first and the second filter coil section output interfaces are connected through an X capacitor, and the third filter coil section input interface is connected with the earth wire through the Y capacitor, and the four filter coil section output interface is connected with the earth wire through the Y capacitor. The EMI filter is characterized in that the second common mode filter coil device is an ultracrystalline filter coil device.