Spectrum processing is a crucial area of signal processing. The conventional time-frequency processing scheme, which relies on finite impulse response (FIR) filter theory in the time domain, presents notable challenges for practical applications due to concerns regarding delay and tap control. In this article, we shall present an analog optical processing technique founded on discrete spectrum processing. Through bandwidth scaling technology, high-precision editing of optical spectrum amplitude and phase with an accuracy of 60MHz is achieved, it provides us with another angle for amplitude and phase processing of signals.