Abstract: The  period 1961-2007 was divided into two by the time node of year 1981, and the change characteristics of the agricultural climate resources both in periodⅠ(1961-1980) and in period Ⅱ (1981-2007) were analyzed and compared. The results showed that under the background of global warming, the average climatic trend rate of ≥10 ℃ accumulated temperature in the middle and lower reaches of Yangtze River in temperaturedefined growth season during 1961-2007 was 74 ℃·d·10 a^-1, and the ≥10 ℃ accumulated temperature in period Ⅱ was 124 ℃·d higher than that in period I. Comparing with that in period I, the safe planting boundary of double cropping rice in period Ⅱ moved 0.79° northward. In 1961-2007, the precipitation in temperature-defined growth season had an overall increasing trend. Comparing with those in period I, the precipitation and the area of ≥767 mm precipitation (water requirement for normal growth of double cropping rice) in period II were increased by 1.6% and 1.13×10.4 km², respectively. The average sunshine hour in temperature-defined growth season in period II was reduced by 8.1%, comparing with that in period I. In recent 47 years, about 91.1% stations in the reaches showed a decreasing trend in sunshine hours. Comparing with that in period I, the reference crop evapotranspirati
on in temperature-defined growth season in period Ⅱ showed a slightly decreasing trend, and its low value region expanded while its high value region narrowed. The beginning date of daily temperature over 10 ℃ was averagely 2 days earlier in period Ⅱ than that in period I, while the ending date was in reverse. The ending date of daily temperature over 22 ℃ was almost the same in periods I and Ⅱ.

Key words: middle and lower reaches of Yangtze River, agricultural climate resources, spatiotemporal characteristics