Abstract: In this paper, the parameters of GM (1, 1) model were considered to be time-varying. By using polynomial function to describe the time-varying parameters of GM (1, 1) model and introducing an optimal production coefficient of the background value into the model simultaneously, the time-varying parameter PGM (1, 1) deformation prediction model was developed. The coefficients of the polynomial were solved by the principle of least squares, and the optimal production coefficient of the background value was determined by searching algorithm. Then, the model was used to predict deformation. The case study showed that the time-varying parameter PGM (1, 1) deformation prediction model has high simulation precision and prediction precision. So it is very suitable to be applied to the deformation prediction of the deformation object.