An optimization man-machine function allocation method for commercial airliner is proposed based on the concept of “man-machine collaboration”in this paper,and applies the functional classification of man-machine system, rank division of automation levels and task decomposition of each flight phase to reconstructing the operation procedures, as well as the man-machine function allocation is optimized and evaluated by expert evaluation method. This man-machine function allocation method provides references for the design of the man-machine interface and formulation of pilot operation procedures of commercial airliner.