The present application discloses a device performance prediction method and a device structure optimization method. According to an embodiment of the present invention, a set of structural parameters and/or process parameters for a semiconductor device constitutes a parameter point in a parameter space, and a behavioral model library is established with respect to a plurality of discrete predetermined parameter points in the parameter space, and the predetermined parameter points being associated with their respective performance indicator values in the behavioral model library. The device performance prediction method comprises: inputting a parameter point, called “predicting point”, whose performance indicator value is to be predicted; and if the predicting point has a corresponding record in the behavioral model library, outputting the corresponding performance indicator value as a predicted performance indicator value of the predicting point, or otherwise if there is no record corresponding to the predicting point in the behavioral model library, calculating a predicted performance indicator value of the predicting point by interpolation based on Delaunay triangulation.