Chum salmon plasma α2-macroglobulin (α2-M) was first puriαed by polyethylene glycol gradient precipitation, gel filtration and anion-exchange chromatography from chum salmon plasma. The α2-M was purified 47.77-fold with a yield of 28.90% towards papain. The α2-M showed molecualr weight (Mw) of 175 kDa and consists of two different subunits of Mw 95 kDa and 80 kDa, respectively. The α2-M was stable towards papain and trypsin at pH ranges from 5.0 to 8.0, and was thermal stable at temperatures below 50°C. The α2-M was applied to Alaska pollock surimi and was able to inhibit the gel weakening in a concentration-dependent manner.