Abstract: The inter-facial tension between the multiphase fluids presents a more prominent capillary force and Jamin effect in narrow pores and throat of the low permeability reservoir, which will cause a significant fluctuation of oil and water flooding pressure. It is necessary to make clear the pressure fluctuation regularity of oil-water two-phase flow in low-permeability sandstone with the factors such as permeability, water saturation, inter-facial tension and core length, so as to provide a guidance for practical production.Experimental study results show that with the lower permeability and greater interface tension, the pressure fluctuations appear more obvious. The degree of water saturation also has an obvious effect on the pressure fluctuation. Improving the permeability of low permeability reservoirs or reducing the inter-facial tension of oil and water will be an effective measure to reduce pressure fluctuations and facilitate the production.