Abstract: Based on the analysis of cast thin-section, conventional physical properties, SEM and mercury injection, the pore structures of JIV reservoir of the Lower Jurassic Yangxia formation are classified. Microscopic waterflooding experiments for sandstone cores are carried out in the reservoirs with 4 main pore structures. The experiment results show that the reservoirs with different pore structures have different percolation features. Fine-throat, low-permeability reservoir and microfine-throat, super-low permeability reservoir are dominated by finger-like percolation, relative fine-throat, high-permeability reservoir by finger-like-net-like percolation and fine-throat, medium-permeability reservoir by net-like-uniform percolation. The remaining oil after waterflooding are mainly in sheet-like and cluster-like distributions resulted from by-pass oil with the secondary of scattered columnar, angular and film-like distribution. The analysis on micro-percolation features of waterflooding in reservoirs with different pore structures could provide basis for reasonable and efficient development of the oilfield