Sandu Shui Autonomous County, under the Qiannan Buyi and Miao Autonomous Prefecture of Guizhou Province. It is located in the southeast of Qiannan Buyi and Miao Autonomous Prefecture, adjacent to Rongjiang County and Leishan County in the east, Libo County in the south, Dushan County and Duyun City in the west, and Danzhai County in the north, with a total area of 2400 square kilometers. In 2021, Sandu County has a registered population of 380,800 and a permanent resident population of 276,100. As of October 2021, Sandu Shui Autonomous County has jurisdiction over 2 subdistricts and 6 towns. On March 3, 2020, the People's Government of Guizhou Province approved Sandu County's withdrawal from the poverty-stricken county list.

Sandu is the only autonomous county of Shui nationality in China. The population of Shui nationality accounts for 67% of the total population. More than 63% of the national Shui nationality population live in Sandu. Among them, the Shuishu custom, the Shui nationality Dragon Boat Festival, the Shui nationality horsetail embroidery, the Shui nationality paper-cut and the Shui nationality double song "Xu Zao" have been included in the national intangible cultural Heritage list. In the 30th year of the Republic of China (1941), Dujiang and Sanhe counties were merged into Sandu County. In 1957, Sandu Shui Autonomous County was established under Qiannan Buyi and Miao Autonomous Prefecture.

In 2021, the GDP of Sandu County was 9.59 billion yuan, an increase of 8.9% over the previous year. The figure was 2.573 billion yuan for the primary industry and 2.443 billion yuan for the secondary industry. The tertiary industry accounted for 4.573 billion yuan, with the proportion of tertiary industry being 26.8:25.5:47.7.