According to the National Bureau of Statistics consumer price statistics methodology system, at present China's consumer price index according to the comparison of different base periods, can be divided into: 2000 prices as the base period of the index (fixed base ratio), the price of the last month as the base period of the index (monthly comparison), the price of the same month of the previous year as the base period of the index (same period), the January to the report of the current year to the price of the same period of the previous year as the base period of the index (cumulative ratio) and the price of the previous year as the base period of the index (cumulative ratio). five indices based on prices in December of the previous year***. The price indexes currently published by the National Bureau of Statistics are mainly the index based on the prices of the same month of the previous year (the same period ratio) and the index based on the prices of the same period of the previous year (the cumulative ratio) for the period from January of the current year to the reporting period.