Disclosed are a method and an apparatus for amplitude estimation of a quantum circuit. The method includes: calculating a first difference value between a current angle upper limit value and a current angle lower limit value corresponding to a to-be-estimated amplitude of a target quantum state, and determining the first difference value as a target difference; determining, a next angle amplification factor and a next flag parameter corresponding to a next iteration step; amplifying the target quantum circuit by the next angle amplification factor; calculating a second difference value between a next angle upper limit value and a next angle lower limit value of the to-be-estimated amplitude, and determining the second difference value as a target difference; and determining, based on an angle upper limit value and an angle lower limit value that reach the precision threshold, a probability estimated value corresponding to a to-be-estimated quantum bit.