The invention discloses an inner-cone spline broaching machine tool, which comprises a base, a broaching tool, a sliding plate, a cutter relieving cylinder assembly, a working device and a driving device. The base is arranged on a machine tool body and is provided with a guiding seat thereon; one end of the broaching tool extends into the machine tool body, and the broaching tool is connected with a stretching cylinder in the machine tool body and can be vertically and slidably arranged on the guiding seat; the sliding plate is sleeved on the guiding seat and is slidably arranged on the base;the cutter relieving cylinder assembly is arranged on the base, and an extending end of the cutter relieving cylinder assembly is connected with the sliding plate; the working device is arranged on the sliding plate and is used for fixing inner-cone splines; and the driving device is arranged on the sliding plate and is used for driving the working device to rotate one indexing unit each time. According to the inner-cone spline broaching machine tool disclosed by the invention, the inner-cone splines are machined by a broaching tool in a broaching manner, the precision by adopting the broaching tool is higher than the precision by adopting gear planning, and the efficiency by adopting the broaching tool is higher the efficiency by adopting the gear shaping and the gear planning; the working device carries out operations, such as automatic indexing, automatic broaching tool feeding, retracting and the like, by the driving device, thus the indexing operation is uniform and reliable, andthe degree of automation is high; and the inner-cone spline broaching machine tool disclosed by the invention is convenient to be detached, and can carry out multiple specifications of inner-cone spline operations by replacing the working device.