Abstract: With the average and maximum daily temperature data during late June and early July (about 20 days every year) recorded by five national weather sub stations in Nanchang in 1960-2012, according to local standards the meteorological disaster indicators of double cropping in Jiangxi province, the change cycle and temporal spatial distribution of weather disaster by the high temperature and its impacts on early rice yield were analyzed The results showed that, (1)the high temperature forced maturity disaster happened every other year in Nanchang, and tended to happen more increasingly and seriously in recent years with the climate warming (2)The distribution of high temperature forced maturity disasters appeared with a little stronger spatial and regular pattern, the severest ones appeared in the south part, some appeared in the middle, but almost none in the north While most of the mild disaster appeared in the middle, and few in north and south of Nanchang (3)In years with mild heat forced maturity disaster, the higher the temperature was, the lower the rate of undeveloped grains and the higher the seed rate were, caused high yields While severe heat forced maturity disasters caused higher rate of undeveloped grains and lower seed rate, reducing yields Therefore in the practical rice production, mild heat almost didn’t affect the early rice yield, but severe heat affected the yield seriously We should take active measures to defend severe heat The study findings will be good for arranging the rice sowing and adjusting the cultivation structure on double rice growth

Key words: High temperature forced maturity disaster, Early rice, Percentage of undeveloped grain, Percentage of partially developed grain, Weight of 1000 grain, Yield