Abstract: The main growth period of double cropping early-rice in 2009 experienced a rule of "two low and one high",through analyzing the observed data obtaining from 8 automatic weather stations.In other words,the double cropping follows three steps: planting seedling stage in spring with low-temperature,booting stage in May with low-temperature and heading and flowering stage with condition of high temperature.The phenomenon above leaded to a higher percentage of empty husks in double-cropping early rice in Dongting Lake area in 2009.Through analyzing the real data series of that time,it observed that the early rice which appeared high empty husks rate were premature and special early-maturing plants.This paper would make deeply influence in the field of improving farming systems and using local meteorological resource enough.

Key words: Dongting Lake, Early rice, Empty husks rate, Genetic analysis