A design method for feedforward active noise control (ANC) system using analog filter. In which, at least one noise collecting system is adopted for collecting a real environmental noise for obtaining a reference signal and a target signal. According to the reference signal and the target signal, a first adaptive system identifying unit is enabled to complete a system identification process for producing a first adaptive filter. After that, a second adaptive system identifying unit is enabled to complete a system identification process based on the reference signal, the target signal and the first adaptive filter for producing a second adaptive filter. After the second adaptive filter is converted to a low-order digital filter, the digital filter is further converted to a physical analog filter circuit. Consequently, a feedforward ANC system comprising the physical analog filter circuit, a pre-amplifier unit, a reference microphone, and a mixer is established.