The present disclosure provides an analog filament impedance circuit, an LED lamp tube and an LED lighting system, the analog filament impedance circuit having a pole frequency and a zero frequency, where: the pole frequency is less than the zero frequency; an equivalent impedance value of the analog filament impedance circuit remains unchanged when an input frequency is less than the pole frequency, and is a first equivalent impedance value; an equivalent impedance value of the analog filament impedance circuit decreases as the input frequency increases when the input frequency is greater than the pole frequency and less than the zero frequency; an equivalent impedance value of the analog filament impedance circuit remains unchanged when the input frequency is greater than the zero frequency, and is a second equivalent impedance value; and the first equivalent impedance value is greater than the second equivalent impedance value.