In recent years, mutton price fluctuates greatly. In order to study the characteristics and causes of mutton price fluctuation, the author took Jilin province as an example and based on the monthly data of mutton price in Jilin province from 2000 to 2017,adopted X-12 seasonal adjustment method and HP filter method to analyze the fluctuation characteristics of mutton price. The results showed that the mutton price in Jilin province showed an overall upward trend, and the main reason for the price change was the influence of irregular factors and seasonal factors. After removing the influence of the two factors, four inter-annual fluctuation cycles of "∩" type, "V" type, "federation" type and "V" type were found in the variation process of the mutton price in Jilin province. Finally, some suggestions were put forward to stabilize mutton prices.