Abstract: On base of preceding research to MJO,in accordance with activities and developing trend of MJO,the Third Experiment to Extended Range Weather Forecast over Yunnan(12th of Nov-15th of Dec)' in 8th of Nov in 2011;By way of contrast and analysis to real weather situation in Yunnan,this paper tests above experiment: In Dry Window Phase,Yunnan daily precipitation anomaly percentage was almost -100% and lack of effective precipitation,which is concordant with experiment result 1 nearly;In Wet Window Phase,there was two times appropriate circulation leading tropical water vapor entering Yunnan,which caused rainy and snowy weather in south and east of Yunnan,that is concordant with experiment result 2 and 3;In late of Dry Window Phase,a light rainy process appeared in area of south and east to middle Yunnan,which shows the estimate to MJO propagation is slower in experiment result;This extended range forecast experiment on background of extreme dry in southwest area of China is successful,and provides practical theoretical foundation for Yunnan province weather station to advance the abilities of extended range forecast to wet/dry and rainy and snowy weather in winter,and contributes to preceding prepare artificial rainfall works to disease dry situation in southwest area in China.