Peanut protein isolate （PPI） was cross-linked with Decapterus maruadsi protein hydralysate （DPH） under the catalyzing of transglutaminase （TGase）, and oil-in-water emulsions of the samples were prepared via the high-pressure homogenization. Then, the effects of the cross-linking on the particle size distribution, the mean diameter per particle surface area, the microstructure and the centrifugal creaming rate of the emulsions were analyzed. The results indicate that （1） TGase accelerates the linkage between PPI and DPH with different hydrolysis degrees; （2） in the electrophoretograms of the cross-linked samples, the subunit bands with low molecular mass （ 14 -31 ku） disappear while the bands with high molecular mass （ more than 97 ku） appear; （3） the hydrolysis degree of DPH greatly improves the emulsifying properties of PPI-DPH, especially at a value of 5.5% ; and （4） the TGase cross-linking improves the emulsifying activity and emulsion stability of the cross-linked PPI-DPH.