The invention belongs to the field of numerically-controlled machine tool life prediction and particularly discloses a numerically-controlled machine tool residual life real-time prediction method. The numerically-controlled machine tool residual life real-time prediction method comprises the following steps that a sensor signal during machining of a numerically-controlled machine tool is acquiredin real time and is preprocessed; the machining working condition is judged according to preprocessed signal data, and the machining process is divided into working subintervals according to different machining situations; tool damages produced in the working subintervals are accumulated to obtain accumulated tool damage indexes; real-time prediction of the residual life of a tool under the target working condition is achieved according to the accumulated tool damage indexes. The numerically-controlled machine tool residual life real-time prediction method does not need additional experimental platform erection and tool dismounting, does not affect normal machining of numerically-controlled machine tools, can achieve real-time prediction of the residual life of the numerically-controlledmachine tools and has the advantages of high prediction speed and accuracy rate.