Based on the validation of dynamic growth simulation model for double-rice through field experimental data, and jointing the climatic change scenarios derived from GCMs outputs and historical climatic data (1960~1990) with double cropping of rice model, objective impact assessment and quantitative simulation experiments on grid points are carried out in the main double-rice areas of the south of Yangtze river valley. Moreover, the effect of a grotechnical adjustment (such as, changes of sowing date and cultivars) on alleviating the impact of climate change are preliminarily estimated and discussed. The results indicate that in the future climatic change scenarios, and under the current planting varieties and agrotechniques, the output of double-harvest rice would be reduced to a different extent. The spatial distributions of yield variation have not only some regularity, but also obvious complexity. Adjustable countermeasure analyses show that the used varieties with long growth duration could increase double-rice yield. Apart from the mentioned above, the sensitivity test with changes of sowing date is also conducted.