Through modulation and demodulation, the chopping technique could effectively reduce amplifier’s input referred noise and offset, and improve the common-mode rejection ability. Therefore, it had been widely used in high-performance analog front-end design. Due to the up modulated offset and low frequency noise, large ripple appeared at the output of the amplifier, which required additional filtering process. An introduction of working principles of chopper amplifiers and mechanisms of output ripple were presented in this paper. A review of state-of-the-art ripple rejection techniques was given, which provided a useful reference for designers adopting the chopping technique.