In this study, the daily average temperatures from September to November in Nantong City were analyzed. According to the critical temperature indices for japonica, rice safe dates of full heading and maturity and the guarantee rate for the safe dates was 50%,80% and 90%,respectively, were obtained. The results showed that the safe dates of full heading during the third 20 years were eight to nine days later than those during the first and second 20 years, and the safe dates of maturity were five to ten days later, respectively. With the trend of global warming, the critical temperature (20 ℃) indices of full heading would not develop the function of guiding production,so reference index was proposed to correct the predicted dates effective cumulative temperature (≥10 ℃) forward day by day, that was the summation of effective temperature from full heading to maturity. The corrected safe dates for full heading of 80% were early 25 days than initial predicted date,and the dates were around September 6th.