Disclosed are a method of forming a plasma coating on a component, an apparatus for forming the coating, a component, and a processing apparatus; the apparatus for forming the coating includes: a vacuum chamber; a first coating material source, a second coating material source, and a component, which are disposed in the vacuum chamber; wherein the first coating material source includes oxygen atoms and yttrium atoms, and the second coating material source includes one of yttrium fluoride, aluminum-oxygen compound, or zirconium-oxygen compound; a first exciting device configured for exciting out the yttrium atoms and oxygen atoms from within the first coating material source; a second exciting device configured for exciting out atoms from within the second coating material source; wherein collision of the yttrium atoms and oxygen atoms excited out of the first coating material source and the atoms excited out of the second coating material source produces a chemical reaction to form on the component a plasma resistant coating including a stable phase of yttrium-based multi-element metal oxide or yttrium-based oxyfluoride. The coating formed using the apparatus has a strong plasma corrosion resistance property.