Ruian, a county-level city under the jurisdiction of Wenzhou City in Zhejiang Province, China, is located in the middle part of China's golden coastline, between Shanghai Economic Zone and Xiamen Zhangquan Golden Triangle. It is the hometown of fish and rice in the South of the Yangtze River. It has jurisdiction over 12 subdistricts, 2 townships and 9 towns, with a land area of 1350 square kilometers and a sea area of 3037 square kilometers. According to the seventh census data, as of midnight on November 1, 2020, the registered population of Ruian was 1,259,200.

Since white crows roosted in the county, people thought it was a good omen, so they changed the name of the county to Rui 'an, which means auspicious and safe.
Rui 'an is one of the second batch of pilot areas of Zhejiang high-quality development and Construction of common prosperity Demonstration Zone; It is one of the top 100 counties for comprehensive strength, one of the top 100 counties and cities for investment potential, one of the top 100 counties and cities for green development, one of the top 100 counties and cities for quality of new urbanization, one of the top 100 counties and cities for quality of agricultural products, one of the national demonstration counties for "Four Good Rural Roads" and one of the top 100 counties for business environment. In December 2020, the Chinese Academy of Social Sciences released "Top 100 Comprehensive Economic Competitiveness of Counties in China", and Shui On ranked 28th. In October 2021, it was selected into the "2021 Top 100 Counties and Cities of China Smart Cities" list.

In 2020, the city's GDP was 103.709 billion yuan, an increase of 3.3% over the previous year. The tertiary industry structure of the national economy was 2.5:44.8:52.7, with the proportion of tertiary industry increasing by 1.2 percentage points over the previous year.