Abstract: In this paper,we analyse the background value calculation in GM(1,1) model,and point out that the structure method of background value using the Newton-Cotes formula in is irreliable,and propose a new method to build the background value based on quadratic interpolation,at the same time,by using the least square method we imporve the initial value in the forecasting formula,and conduct a short-term prediction by the improving method.Both the analysis in theory and the simulation result show the effectiveness of the proposed approach,and give a new way to improve the prediction accuracy.

Key words: grey system, background value, quadratic interpolation, GM(1,1) model