Abstract:［Objective］In order to reduce CO2 emission and lower the cost of microalgal industrial production at the same time，a technology was developed to combine CO2 sequestration with microalgal cultivation． ［Methods］The technology was based on rapid pH drift and high pH adaptability of two microalgal species，Chlorococcum alkaliphilus MC-1 and Spirulina platensis． A simple structure，CO2 leakage prevention covering-box，was designed to collect CO2 escaped from culture medium when CO2 gas was injected into the culture． ［Results］In the small-scale outdoor cultivation of MC-1，CO2 escaped from culture was all absorbed by culture with the help of covering-box． Results from the pilot-scale cultivation of S． platensis (HS 331) combined with the CO2 addition technology show that the cost of carbon source was remarkably reduced and deposition of CaCO3 and MgCO3 was effectively avoided． In addition，the average productivity was rather high ［9.54g/(m2·d1)］．In the large-scale cultivation of S． platensis，the annual yield was increased by 20% and high quality product was obtained with the CO2 addition technology． In addition，66% of NaHCO3 was saved，more than 58% of carbon cost was reduced，and about 45 tons of CO2 was sequestrated． ［Conclusion］ The technology was successfully applied in industrial production of S． platensis and the cost of producing S． platensis was dramatically reduced． The study would provide new insight into carbon dioxide sequestration．