Agriculture is affected by climate change most sensitively, especially prone to be affected by drought and flooding, causing serious losses. Researches on the threshold of meteorological disaster inducing factors at point scale have been carried out, such as formative mechanism in meteorological disaster inducing factors, artificial experiments of drought and flood disaster and crop simulation models based on field plot, etc. Moreover, researches at surface scale have appeared, such as mathematical statistics in the basin, drought-flood index of meteorological disaster inducing factors and the meteorological disaster inducing threshold based on the theoretical hypothesis. The major problems are as follows: formative process in meteorological disaster inducing factors is not clear on the content of study; and as for the study method, there is no suitable experimental support for meteorological disaster inducing factors and its probable threshold at surface scale achieved through statistical approach. The advanced researches need to be developed as follows: after refining the formative process of meteorological disaster at point scale and finding the law, the disaster inducing threshold is defined. It is important to achieve the transformation between point and surface scale. The conversion tool is decided to the successful yardstick reasoning and scaling convert.