The invention provides a cutter bottom edge cutting evaluation and feed sped optimization method in a four-axis rough machining axial-flow integrated blade disc. With consideration of a spatial geometric relationship between an axial-flow integrated blade disc and a cutter during the machining process, an instantaneous cutter position in a machining coordinate system is calculated based on a constant acceleration insertion algorithm; a transformation matrix is established according to the machining process and instantaneous positions of a cutter center point and a cutter shaft direction in a workpiece coordinate system are calculated; an instantaneous feed rate of the cutter center point is calculated, a maximum instantaneous feed rate of the bottom edge is defined, and bottom edge cuttingis evaluated; and then the feed speed of the cutter is optimized according to the maximum instantaneous feed rate of the bottom edge and the total machining efficiency. Therefore, the cutting participation degree of the cutter bottom edge during the four-axis machining process is calculated and analyzed precisely and the corresponding cutter feed speeds of all cutting position points needing optimization are identified; the feed speeds can be optimized based on the high machining efficiency; and the adverse effects caused by the bottom edge cutting are reduced finally.