In industrial high-pressure pump systems, the high pressure pump plunger plays a decisive role in pressure stability, sealing performance, service life, and maintenance cost. Selecting the correct high pressure pump plunger material is therefore critical for reliable long-term operation. Among the available options, ceramic, stainless steel, and aluminum alloy plungers are the most commonly discussed. But are they equally suitable for industrial applications? And how should users decide which plunger material best fits their operating conditions? This article provides a clear engineering-based comparison of ceramic plunger, stainless steel plunger, and aluminum alloy plunger designs, with practical guidance for industrial users.