Abstract: To solve the oil production increase of Dagang Oilfield,several TOR(tertiary oil recovery) technologies have been studied to improve the oil recovery rate.Microbial enhanced oil recovery is a rapidly developing technology in past several years.Based on the biotic characteristics of microbe,the injection crafts is very important for microbial enhanced oil recovery.To guarantee the injection concentration of microbe,a series of research have been conducted,such as the development of injection appliance,the optimization of injection crafts and the design of injection schemes.The survival rate of microbe reached 98.5% for field experiments at 7 blocks,and the oil recovery rate was increased by 2.7%.The field application shows that there is a brilliant prospect for microbe injection.