Abstract: Test techniques such as the oil water displacement test,the microscopic water drive test and the nuclear magnetic resonance were applied in this paper to study water drive mechanism and the affecting factors of water drive efficiency in the main oil layers of ChenBao oil field.The results showed that the difference of water drive efficiency within each sandlayer group of the oil field was mainly affected by the macroscopic heterogeneity of reservoirs,the small scopic heterogeneity of rocks and oil/water viscosity ratio,and was affected slightly by permeability in some range of permeability.On microscopic level,water drive efficiency was mostly affected by pore structure.