GDP is a measure of the economic situation of a comprehensive index. China's quarterly GDP accounting and data dissemination procedures: preliminary accounting of the number on the 20th in the season announced around; initial check of the season, announced around 110; final verification of the end of the following year and released. At the same time China's quarterly GDP data for the quarter is usually a total accounting of the way, and is not seasonally adjusted. In the paper, the GDP data is used to do something and then use X-12-ARIMA module in the SAS statistical software to adjust seasonality China's GDP, to quarter analysis and forecast. Since 2005, China's GDP statistics calibre adjustments needed to quantify.