A correcting method for a display apparatus is provided. For N original grayscale combinations, color performances of the display apparatus are respectively measured to generate N measurement results. A set of color blending equations are utilized for M original grayscale combinations according to the N measurement results to generate M blended results. From the N measurement results and the M blended results, P color performances respectively most approximate to P target performances are identified. The P target color performances correspond to P target grayscale combinations. The P color performances correspond to P original grayscale combinations in the (N+M) original grayscale combinations. A look-up table for correcting the display apparatus is established according to the P target grayscale combinations and the P corresponding original grayscale combinations.