The aim of this paper is to study the changing law of fi lter media properties under high-pressure conditions, and for this

purpose, an experimental setup was established to measure the properties of fi lter materials at a maximum pressure of

5 MPa. By observing the experimental phenomena produced under diff erent pressures, combining the experimental data

and experimental phenomena for qualitative and quantitative analyses, the fi lter media performance change pattern under

diff erent pressures was obtained. The experiments were carried out at a pressure of 1–5 MPa, and the detailed experiments

were conducted on the pressure drop, saturation and the liquid distribution pattern of the fi rst and last layers of the fi lter

material. The experimental results show that the liquid fi lm on the surface of the fi lter media becomes progressively thinner

with increasing pressure, and the jump pressure drop becomes smaller while the saturation increases. The saturation

of the fi rst layer of the oleophilic fi lter media increased by 30% and the saturation of the last layer of the oleophobic fi lter

media increased by 80% when the pressure was increased from 1 to 5 MPa. In addition, the results show that with increasing

pressure, the surface tension of the droplets decreases and the surface tension of the DEHS decreases from 28.72 to 25.26

mN/m. The capillary force of fi lter media B was reduced from 0.20 to 0.13 mN, a 35% reduction in capillary force which

changed the distribution of droplets on the fi bres and enhanced the wettability of the fi lter material. This discovery is of

great signifi cance for understand ding the variation pattern of fi lter media performance under high-pressure conditions, and

provides a basis for the design and manufacture of fi lter elements for high-pressure occasions.