A pipeline analog-to-digital converter (ADC) having a digital calibrating circuit is described. The pipeline ADC includes a pipeline converting circuit and a digital calibrating circuit. The pipeline converting circuit has a plurality of one-bit stages, and converts an analog input signal into a first digital signal having a plurality of bits. The digital calibrating circuit extracts calibration coefficients for the one-bit stages, and calibrates a feedback signal based on the calibration coefficients and the first digital signal to generate a second digital signal having a plurality of bits. The pipeline ADC may perform digital calibration automatically with good linearity.