There are two kinds of filtrations during drilling and completion operations. One is the static filtration after stopping the circulation of drilling fluids. The mud cake thickness increases gradually and the filtration rate decreases with time. Another is the dynamic filtration when the mud cake formed is eroded by circulating drilling fluids. There is no a proportional relationship between static filtration and dynamic filtration of differential drilling fluids, therefore, the measurement of dynamic filter loss is particularly important. The Model HDF-1 HTHP Dynamic Filter Press has overcome the shortages of various traditional static filter presses and enabled the measured results are close to the borehole conditions. It can be used to measure the filtration property of drilling fluids and cement slurry accurately and safely under static and dynamic conditions. The usage of the instrument can provide the reliable data for realizing scientific, rapid, high quality and safe drilling.