Abstract: Xing'anling reservoir of the Hailar oilfield belonging to the Ultra-low permeability reservoirs,and water sensitivity index was higher,and the effect of conventional waterflood development was poor.In this paper,for Xing'anling reservoir characteristics researched the feasibility of CO2 flooding for the ultra-low permeability of strong water sensitivity reservoir through laboratory experiments, the preferred test area,optimize reservoir development programs and tracking of dynamic analysis.CO2 flooding of Xing'anling reservoir has been made in the Initial results of the field tests,and provided technical support to speed up the the Hailar oilfield production.