Drought index analytical method which was based on relative moisture index was used to study the decadal variation characteristics of temporal-spatial distribution of spring drought in recent 55 years in southwest China according to southwest China's climatological information between 1958 and 2012. The result showed that the frequency of spring drought in southwest China had a distribution character of progressively increase from northeast to southwest, regions where have more than 80% of the emergence frequency of spring drought are distributed on Yunnan Plateau, Chuanxi Plateau and southwest mountainous areas of Sichuan, on Chuanxi Plateau and some part of southwest mountainous areas of Sichuan, low-grade drought appears almost every spring. Severe drought and extreme drought are more likely to appear on south part of Chuanxi Plateau, southwest mountainous areas of Sichuan and north regions of Yunnan Plateau. The average area where low-grade drought, medium-grade drought and heavy drought in southwest spring appeared take over 42%~45%、16%~29%和1%~8% of the total research area respectively. The appearance area of low-grade spring drought has a character of fluctuating change, while medium-grade drought and heavy drought had decreasing trends on their appearance areas. The intensity of spring droughts are higher in Yunnan Plateau, Chuanxi Plateau and southwest mountainous regions of Sichuan, but the oscillation amplitude in these regions are small and the interannual fluctuations are small too. The spring drought intensity in Chuandong Basin and Guizhou Plateau are relatively smaller, but the oscillation amplitude in these regions are greater as well as the interannual fluctuations. The spring drought in southwest had gone through five obvious varying stages, that is, in 60s of twentieth century the drought intensity gradually enhanced; in 70s the drought intensity gradually weakened; in 80s and the beginning of 90s, drought intensity enhanced again; from the middle of 90s till 2004, the drought intensity weakened again. The index of southwest spring drought had an obvious 2~3a and 7~8a periodical oscillation. Low-grade spring drought occurred in a fluctuation way, for severe and extreme drought, their occurred areas had a receded trend. After the year 2005, drought index cumulative departurehad a negative growth trend and drought intensity enhanced gradually.It is predicted that next decade drought intensity will be enhanced.