According to size distinguish weak and existing lower limit of the Deng’s grey correlation degree of different schemes under the same attribute, a new correlation degree based on the exponential function is defined. The resolution of the improved correlation degree of different schemes under the same attribute is higher than that of the original correlation, and the properties of the improved correlation degree is proved. The attribute weights are determined by the exponential correlation degree, and a optimization model can be built to solve the time weight based on the deviation and grey entropy. Finally, the proposed method is used to analysis and evaluation of operating performance of private enterprises in the Henan province of a prefecture level city, and the result shows the its feasibility and effectiveness.