In order to get biodegradable lubricant, trimethylolpropane tri-ester was prepared using palm oil as material. Gas chromatographic internal standard method was adopted to analysis the production rate of tri-ester. Optimized by response surface methodology, the production rate of tri-ester was up to 88.75%. Purified by molecular distillation, the purity of the tri-ester was up to 98.6%. The structure of tri-ester was con?rmed by FT-IR and MS. Then, the tri-ester was compounded with PB-1300 (polyisobutylene), T803B (poly-α-olefin), BHT (2,6-Di-tert-butyl-4-methylphenol) and S-80 (sorbitol monoglycerides), to prepare lubricant. The lubricant had good viscosity-temperature performance and outstanding security stability, and it was also non-toxic and biodegradable.