The fluid does not follow the Darcy flow in low-permeability reservoir, so the influence of threshold pressure gradient should be considered in the development of low-permeability oilfields. And the pore structure is the main factor affecting the threshold pressure. This paper combines conventional logging data with laboratory experimental results, uses the trial method to calculate the threshold pressure gradient at different well distances and forms a chart. The power function regression of each curve is carried out, and finally the formula for establishing effective displacement pressure and conventional logging parameters in low permeability reservoirs is derived. According to this, the comprehensive classification and evaluation method for low-porosity and low-permeability reservoirs is discussed. In the exploration and development process of low-porosity and low-permeability oil reservoirs, it is of great significance to accurate evaluation of reservoirs and select the relatively high-quality reserves for improving the production efficiency and making the oilfield development plan. This method is applied to F oilfield, and the classification standard of Class 4 reservoirs in F oilfield is obtained, Class I and Class II reservoirs can be effectively displaced by water flooding, Class III and Class IV reservoirs need to use gas flooding or explore new development methods, so as to provide a reference for the efficient development of F oilfield.