The embodiment of the invention discloses a quadrature amplitude modulation qubit demodulation method. The method includes the steps of predetermining a sub-area which each constellation point belongs to on a gray constellation complex plane corresponding to a bit position to be demodulated, wherein each sub-area corresponds to a perpendicular bisector; determining a sub-area which each constellation point containing the corresponding bit position to be demodulated and mapped by a received symbol on the gray constellation complex plane corresponding to the bit position to be demodulated; calculating the perpendicular distance between each received symbol containing the corresponding bit position to be demodulated and the corresponding perpendicular bisector, and making the distances serve as the qubit values of the bit position to be demodulated, wherein the qubit values are positive when each received symbol containing the corresponding bit position to be demodulated is located on the side, with the first bit value, of the corresponding perpendicular bisector, and the qubit values are negative when each received symbol containing the corresponding bit position to be demodulated is located on the side, with the second bit value, of the corresponding perpendicular bisector. The invention further discloses a quadrature amplitude modulation qubit demodulation device. By means of the quadrature amplitude modulation qubit demodulation method and device, the qubit demodulation efficiency can be improved.