In order to research the fluctuation law of price of pork in Beijing City and determine its fluctuation cycle, we use level indicator analysis, speed indicator analysis, the coefficient of variation, the seasonal adjustment model and the HP filter method, to analyze the data on the market price of pork in 8 wholesale markets in Beijing City during the period 2002-2011. The results show that the annual price of pork in wholesale markets in Beijing City shows a gradual upward trend; during the period 2002—2011, the price of pork in Beijing City experienced three full fluctuation cycle, and each fluctuation cycle was roughly 38 months; the price of pork within the year shows a trend of "one trough, one crest", and the interval of high prices is mainly concentrated in June-December; the amount of pork for sale within the year is basically inversely correlated with the price. Therefore, we should strengthen the monitoring of pig production information and market information, to ensure the sufficient supply of pork, and stabilize the market price of pork. In addition, according to the variation law of the market price of pork, improving the purchasing, storage and allocation work mechanism of the reserve meat is also necessary to stabilizing the market price of pork.