Abstract: In order to improve the usual methods of parameter estimate in the Panel model, the ratio of two spectral eigenvalues of Panel model is analysed and several methods to adjust the ratio are provided. Applying these methods, it derives the best estimator under MSE criterion in some subclasses of invariant estimator of variance component in the model; and derives a class of unbiased two-stage estimator for the regression coefficient. Also, expression of adjusting the ratio so as to decrease the covariance matrix in this class is given.