To enhance the oral bioavailability (BA) of curcumin (CUR), we applied 1 wt% CUR-loaded lipid nanoparticle (LNP) system prepared with tristearin (TS) and short (Brij S10) / long (Brij S100) PEGylated surfactants. All LNPs were colloidally stable under high ion strength and pH 3 conditions regardless of the PEG chain length. However, the long-chained PEGylation prevented LNP surface better than the short-chained PEGylation from the lipase/bile salt adsorption according to ζ potential results after treatment of lipase and bile solutions. Actually, the short-chained LNPs were digested rapider than the long-chained one in the simulated small intestinal condition due to the faster displacement of PEGylated surfactants on LNP surface by bile salts. Furthermore in the rat model pharmacokinetics for oral administration of CUR, the long-chained LNP group had 10.62-fold BA of native CUR group due to the coabsorption of CUR with the mixed micelles made after gastrointestinal digestion, and had 4.57-fold BA of the short-chained LNP group despite the same molarity use (17.058 mM) of both emulsifiers due to the reduced digestion rate by long-chained PEG on LNP surface. In conclusion, since CUR incorporated in LNPs was improved in the bioavailability, the designed LNP system may serve as an encapsulation strategy to enhance the bioavailability of non-bioavailable nutraceuticals in foods.