This report describes the assessment framework，data collection and analysis methods，and indicator calculation method of China Open Public Data City Index，evaluating 173 cities across the country that have launched open government data platforms，and give suggestions for future development. The report shows that Shanghai and Qingdao have the best overall performance. In the four key dimensions，Shanghai ranks first in Readiness，Platform and Use，and Yantai ranks first in Data. The report uses a four-year cumulative score of “ODympic” to reflect a place’s continuous level of open data in the past four years（2018-2021），and finds that Shanghai has the highest score，followed by Guiyang，Qingdao，Shenzhen and Jinan. The report further shows the city benchmarks in four key dimensions：Readiness，Platform，Data and Use，and put forward a series of suggestions from the aspects of institution supply and organization support，platform improvement and sustainable operation，data quantity enhancement and quality assurance，data use and ecology cultivation.