Abstract: The study of the grain output changes is mainly based on the single scale before, and few is on the multiple time scales. So the wavelet analysis has been used to analyze the grain output in Jiangsu Province during the Last 50 years at multiple time scales. The results show :① The grain output in Jiangsu has gone through five stages. ②The grain output has 3year,13year and 25year characteristic time scales , and the time scales tend to become longer and it indicates that the changes of grain output of Jiangsu Province become slow. ③The grain output has 13year and 25year periods and the 25year period is especially outstanding from the wavelet variances analysis .④Whether at the big scale or at small scale, the grain output of Jiangsu Province will reduce in the recent years on the base of the analysis of the fig of the wavelet coefficients. We have analysed the reason and have proposed some suggestion on how to guarantee the security of grain output of Jiangsu province.

Key words: Jiangsu Province, grain output, wavlet analysis, Characteristic time scales