Copolymers were prepared by polymerization of maleic anhydride (MA) and α-olefins such as 1-octene, 1-hexadecene and mixed olefin for metal-working lubricants. 1-octene(C8)-maleic anhydride copolymers were optimized at MA-C8-Bz2O2-C2H4Cl2 mol ratio 1 : 1.3 : 0.02 : 4 in inert gas in 6 hrs. Also, 1-hexadecene(C16)-maleic anhydride copolymers were optimized at MA-C16-Bz2O2-C2H4Cl2 mol ratio 1.1 : 1 : 0.02 : 4 in inert gas in 6 hrs. The copolymers were partially esterified with alipahtic alcohols or polyethylene glycol methyl ethers(PEGMEs) to obtain ester copolymers, which are useful as lubricating oil additives in 60% yields. Those polymer-esters were mixed with KOH and water to use as water-soluble lubricants.