Pea protein isolate (PPI) is a valued sustainable protein source, but its relatively poor functional properties limit its applications. This study reports on the effects of cold argon plasma (CP) treatment of a 15 % (w/w) PPI solution on the functionality, structure, and oxidative characteristics of PPI, as well as its application in 3D-printed plant-based meat. Results indicate that hydroxyl radicals and high-energy excited-state argon atoms are the primary active substances. A decrease in free sulfhydryl content and an increase in carbonyl content were observed in treated PPI, indicating oxidative modification. Compared to the control group, the gel strength of PPI was increased by 62.5 % and the storage modulus was significantly improved after 6 min treatment, forming a more ordered and highly cross-linked 3D gel network. Additionally, CP significantly improved the water-holding capacity, oil-holding capacity, emulsifying activity, and emulsion stability of PPI. The α-helix and random coil content in PPI decreased, while the β-sheet content increased, resulting in a more ordered secondary structure after CP treatment. Compared to untreated PPI, the consistency coefficient (K) increased from 36.00 to 47.68 Pa·s. The treated PPI exhibited higher apparent viscosity and storage modulus and demonstrated better 3D printing performance and self-supporting ability. This study demonstrates that CP can significantly enhance the functional properties of PPI, providing great potential and prospects for improving the printability of 3D printing materials and developing plant protein foods with low-allergenicity.