Abstract: Since 2011the production and output of vegetable in China have exceeded that of grain and become the largest agricultural product so that its production affects the stability of the national market.Owing to the production of vegetable being affected by many factors,the available data of the production have three shortages: large volatility,small sample size and poor information. In order to predict the vegetable yield in China in a short term,we apply a GM(1,1)model based on least square method and the gray system prediction theory, where the least square method is used to weaken the large fluctuation of data and to reduce the randomness. The predicting model is established with the vegetable production data of 2009to 2014and is showed with the data of 2014to have good forecasting accuracy.The forecasting results show that the production of vegetable will continue to increase in the next three years,which can provide some references for other related prediction, for facilitating the macro-regulation to the future vegetable market to maintain market balance and avoid risks of price fluctuation.

Key words: Gray system, Vegetable yield, GM(1,1)model, Least square method