Abstract： Based on superposed loglinear process (SLLP), a whole lifecycle reliability assessment method for multiple numericallycontrolled (NC) machine tools with minimal repair was proposed. A bathtub curve model, which includes early failure period and wear failure period, was presented. The lasting time of early failure period was quantitatively analyzed, and the point maximum likelihood and interval estimators of model parameters and reliability indices were given. An example of real data with failure truncation from multiNC machine tools was taken to prove the proposed method. The results of AIC and goodnessoffit show that the SLLP model is better than that of the superposed powerlaw process model, which is suitable for whole lifecycle reliability assessment of NC machine tools.