The invention relates to a method for machining and detecting a slender axle-like part with continuous conical surfaces, belonging to the field of part processing. In the method, through using the characteristics of a numerical control machine, a slender axle-like part with continuous conical surfaces is machined through compiling a corresponding numerical control machining program; and in the process of machining, through measuring corresponding numerical values of the machined part in time and then adjusting the program according to the measured numerical values, a finish machining is performed on the part, thereby not only achieving the purpose of simply and rapidly carrying out accurate and effective detection on a plurality of conical surfaces of the machined part, but also ensuring that both the accuracy and size of the machined part can meet the design requirements.