Hydraulic seals play an important role in the integration of hydraulic pneumatic, if a hydraulic pneumatic components product seals do not pass, then this hydraulic pneumatic components products are not a good product. There are many factors that affect seals. First of all, pressure is an important reason to affect the quality of seals, the level of pressure, the length of pressure cycle changes, the seal damage (such as extrusion) has a great impact. The higher the pressure, the greater the impact of other factors on the performance of the seal, such as temperature, speed, seal material, gap between piston and cylinder, gap between piston and cylinder head. Another is the temperature and friction, it is difficult to describe the maximum use temperature and minimum use temperature of a seal material, because this is the result of a series of factors combined with the effect. For both piston and piston rod operating temperatures are different, they should be selected differently. Another is the surface roughness of the seal product, surface characteristics, pressure, medium, temperature, seal material, seal type and speed of motion these are the factors that affect the seal. The last one is surface treatment, and experience shows that the characteristics of the surface of the cylinder piston and piston rod have a great influence on the life of the seal. Surface properties are often defined by the value of surface roughness Ra, which is the arithmetic average of surface shape deviating from the absolute value of the centerline. However, some values do not fully represent the effect of the surface condition on the seal, because even under the same roughness, different surface shape characteristics can lead to different degrees of seal wear on the seal.