In order to improve the performance of oil well cement stone, the mix proportion of oil well cement and active filler was optimized depending on the model of Aim and Goff. The cement stones were investigated via compressive strength testing, permeability testing, MIP, XRD, DSC TG and SEM, and then the computed results of the model were certificated. Results show that 20% of the content(by mass) of active filler for oil well cement is optimal. The compressive strengths of samples cured for 7d and 28d at 80℃ are 35.1MPa and 39.4MPa respectively, and they increase 33.5% and 45.9% compared with pure oil well cement system respectively. The samples of cement stone does not permeate at displacement pressure of 7MPa and 15MPa (the permeability of pure oil well cement system is among 3.02×10-67.68×10-6μm2). Porosities are 25.7% and 21.3%(by volume), which decrease 18.4% and 24.7% compared with pure oil well cement system respectively. When the content of active filler is 20%, the intensities of XRD and endothermic peak of Ca(OH)2 in cement stone cured for 7d at 80℃ decrease obviously. Furthermore, the degree of densification of cement stone is improved.