Abstract: The CO₂ storage in reservoir can not only be used for CO₂ reduction，but also can be used for EOR，which is a promising project.The results show that there is a three-stage cap rock which is composed of interior sealing cap，which is an important reason for CO₂ well storage.The optimal CO₂ storage capacity in Qiaojiawa oil region is 365.21×10⁴ t.A monitoring system was built called “strata-surface-atmosphere” trinity，which achieves the effective monitor.The total CO₂ injected in reservoir is 5.9×10⁴ t.The monitoring results show the storage condition is well.The pioneering project conducted by Yanchang petroleum provides a good demonstration for CO₂ storage in reservoir geology in China.