Direct Air Capture (DAC),as an emerging negative emission technology for removing CO2 directly from the atmosphere,plays a vital role in achieving global climate goals. However, optimizing DAC siting to support its large-scale deployment remains achallenge. Based on existing literatures,a set of DAC project siting index system was developed,categorized into 4 primary indicatorsincluding CO2 sequestration and transportation,energy supply,environmental characteristics,and social impacts,covering 21 secondaryindicators. Using this index system,a questionnaire survey was conducted targeting government officials,researchers,and industry expertsto assess the significance of these indicators in influencing DAC siting decisions. The findings underscore DAC site selection as a multi-factor decision-making process,with significant variations in the importance of different factors for different technology types. For high-temperature absorption technologies,4 primary indicators,ranked by importance,are environmental characteristics,energy supply,socialimpacts,sequestration and transportation. For low-temperature adsorption technologies,4 primary indicators,ranked by importance,areenvironmental characteristics,social impacts,energy supply,sequestration and transportation. Notably,temperature is crucial for sitinghigh-temperature absorption technologies,while land use and relative humidity are critical for low-temperature adsorption technologies.Furthermore, significant divergences were observed among experts regarding certain indicators (such as air quality, nuclear energysupply), indicating insufficient research on how these factors specifically affect DAC performance. Future research should furtherenhance DAC siting under multi-factor impacts,which is crucial for the large-scale deployment of negative carbon technologies.