In order to probe into the dynamic mechanism of the oolitic limestone under the deep burial condition, the authors designed a high-pressure pump controlled device to simulate the process of dolomitization. The dolomitization experiment on oolitic limestone was conducted under the 40 MPa comparative lithostatic pressure and 150℃ geothermal temperature (equivalent to the condition of 4000 m deep burial) for 15 days. The results show that the rock structure was slightly changed, the content of Ca2+, the main component of the tail liquid, increased from 0 mg/L to 337 mg/L, and Mg2+ decreased to 2380 mg/L. Meanwhile, electron microprobe analyses show that the content of CaO in solid sample decreased from 61.000% to 60.830%, while the content of MgO increased from 0.296% to 0.350%. It is considered that the main elements Ca and Mg in solid and liquid samples experienced growth-and-decline changes before and after the reaction. An integrated comparative analysis was conducted by means of microscope observation, scanning electron microscope, stereoscopic microscope, electron microprobe analysis and X-ray diffraction analysis. Although the experiment failed to produce dolomitization, the result could provide constraints and experimental data support for further understanding of the conditions of dolomitization.