In this study, euglena protein solution was used as raw material, and euglena protein was extracted by foam separation method. With the recovery and enrichment ratio as indexes, the effects of pH, liquid volume, temperature and dilution ratio on the recovery and enrichment ratio of euglena protein were investigated by single factor and response surface design. At the same time, the functional characteristics of euglena protein were studied, and the structure of the protein was analyzed by Fourier transform infrared spectroscopy and dual-beam ultraviolet-visible spectrophotometer. The secondary structure of the protein was identified by Peakfit Version software, and the amino acid composition of euglena protein was determined by amino acid analyzer. The results showed that the optimum conditions for foam separation of Euglena protein were as follows: pH5.5, liquid volume 300 mL, temperature 30 ℃, and 15 times of dilution. Under these conditions, the protein recovery rate was 94.27% and the enrichment ratio was 4.18. The maximum water holding capacity of protein was 7.27 g/g at 60 ℃, and the maximum oil holding capacity was 14.74 g/g at 40 ℃. The emulsifying ability, emulsifying stability, foaming property and foam stability of euglena protein increased at first and then decreased with the increase of mass fraction.. FT-IR and UV showed that euglena sp. protein had a typical protein peak, and its secondary structure indicated that euglena sp. protein was mainly β-folded. The contents of essential amino acids and hydrophobic amino acids in protein are 35.28% and 50.81%. The results provide experimental basis for the study of euglena protein.