Abstract: The formation mechanism and quantitative evaluation of secondary pore is the key problem for deep sandstone reservoirs. The experiments on dissolution-precipitation behavior of formation water and minerals in reservoirs were carried out by using high temperature and pressure geochemical experimental simulation system based on the present temperature and pressure conditions of Minfeng sub-sag in Dongying depression and the corresponding formation water characteristics. The experimental results show that under the current formation water and temperature pressure conditions, quartz and plagioclase could undergo dissolution, and the solubility increased with the increase of temperature, while calcite underwent cementation, and its growth rate changed little with the increase of temperature, generally concentrated at around 70×10⁻³g/L. Based on the experimental simulation results, taking into account factors such as permeability flow velocity, precipitation velocity, burial time, porosity and other factors of the formation, a mathematical model of secondary porosity due to dissolution of sandstone reservoirs was established. According to the mathematical model calculation, the CaCl₂ water type at 171℃ in Feng 8 well had the maximum contribution value of 2.52% to the physical properties of the reservoir, which was the most favorable water type and temperature for the development of secondary porosity zone within the simulation depth range of this well. The model calculation showed that the seepage rate was the main factor affecting the development of secondary dissolution pores. Combined with the diagenetic phenomenon of actual reservoirs in Feng 8 well, it had good correlation and obvious dissolution of quartz and feldspar, development of carbonate minerals in the form of cementation and metasomatism, which was consistent with the experimental simulation results. Based on mineral solubility, mineral content, reservoir temperature and pressure conditions and formation water chemistry, the quantitative calculation model established in this paper can predict the deep secondary pore development zone.