Abstract: Based on the properties of reservoir rocks, the authors of this paper advance the methodology of the study on the diagenesis of feldspar and quartz in reservoir rocks with developed functions using reformed electron probe. It is revealed that secondary porosity of reservoir rocks are mainly resulted from potash feldspar dissolution. The microelement content of the secondary enlargement margin of the the feldspar and quartz, somehow, would reflect the chemical conditions of the pore fluids during diagenesis. Therefore, it can be used as an auxiliary tool to classify diagenetic stages, and it will provide leads and explore avenues for the further studies on reservolr rocks.