Abstract: In recent years, pig price becomes increasingly abnormal fluctuant, which causes widespread concerns in the whole society. Based on historical price data, pig price prediction applies scientific quantitative methods to predict future pig price. Therefore, price prediction can help support scientific decision-making for pig producers. Given the particularity of pig price, the article applied grey system theory, based on the weakening buffer operator and set up GM (1, 1) prediction model, then used residual error, grade ratio deviation, correlation degree and posteriori error four kinds of error checking methods to test the reasonability and the prediction accuracy. The error test results are P⁰=97.33%＞90%、ρ(avg)=4.6613%＜10%、r=0.8441＞0.6 and P=0.7778. The error test results indicate that the gray system theory is appropriate when applies to pig price prediction, and has high prediction accuracy. According to GM (1, 1) prediction model the pig price of the next three years hog prices are 16.72 Yuan/kg, 15.26 Yuan/kg, and 17.42 Yuan/kg respectively. Comparing to 2013, these prices increase 14.84% , 4.81% and 19.64% respectively. Prediction results show that there exist some fluctuations in future pig price, and pig price will increase gradually.