A prognostic method and a prognostic apparatus for a processing apparatus are provided. In the steps of the prognostic method, multiple sensor data of a component of the processing apparatus and a heterogeneous data are obtained, multiple health indicators of the component are obtained by the multiple sensor data, a regressive characteristic function and an adjustment function are obtained according to the health indicators, the adjustment function corresponds to the heterogeneous data, a prediction function of health indicator is obtained according to the regressive characteristic function and the adjustment function, and a predictive value of health indicator is obtained according to the prediction function of health indicator to estimate a usage status of the component.