摘要：The occurrence of bumper or poor grain harvests in ancient China plays an important role in explaining how past climate changes affected the *** of the lack of long-term continuous and high-resolution quantitative data for reconstructing the series of grain harvests in ancient China,understanding of the impacts and mechanisms involved in climate change is *** study presents a method designed for reconstructing grain harvest series by quantifying grain output levels based on the descriptions in historical *** method involves setting the grain output level for each year based on very specific meanings of different words,calculating a yield index based on the structure of each level and assessing grain yields(bumper or poor harvests)every 10 ***,1636 records related to grain yields(including crop yields,food security,agricultural disasters,grain prices,grain storage and people's livelihoods)for each year were retrieved from history books called the Twenty-Four ***,using this method,a 10-year resolution graded grain harvest series from the Western Han Dynasty to the Five Dynasties(206 BC–960 AD)is ***,the relationship between the variations in temperature and precipitation and the fluctuation of grain yields is *** results show that from the Western Han Dynasty to the Five Dynasties,bumper,average and poor harvest decades accounted for 33.3%,39.3%and 27.4%of the 1,166-year period,*** grain yields during 206 BC–960 AD can be divided into three stages:a period of bumper harvests during 206–51 BC,poor harvests during 50 BC–590 AD and bumper harvests during 591–960 *** harvest decades typically experienced a warm climate with normal or high levels of precipitation,while poor harvest decades had a cold and dry climate.A positive correlation was found between temperature and grain yield because a warm climate allows a full use of *** observed relationship between precip