Abstract: Ultrafiltration separation technology was used to concentrate yellow serofluid in order to obtain protein efficiently and reduce the pollution of yellow serofluid and improve its comprehensive utilization. On the basis of single factor experiment, the ultrafiltration process of yellow serofluid was optimized by response surface. The contents of protein and total sugar, biochemical oxygen demand(BOD), chemical oxygen demand(COD) and metabolomics of yellow serofluid before and after ultrafiltration were determined. The results showed that the optimal parameters of ultrafiltration concentration of yellow serofluid were as follows: pH6.2, operating pressure 0.22 MPa, temperature 31 ℃. The membrane flux was (51.8±1.3) L/m²·h, the protein interception rate was 76.84%, the total sugar transmittance rate was 79.10%, and the removal rates of BOD and COD were 69.27% and 61.03% respectively. Metabolomics analysis of the concentrated and translucent solutions showed that there were significant differences in the contents of 114 compounds in the concentrated and translucent solutions. The results show that ultrafiltration can effectively separate proteins and sugars from yellow serofluid, and has a certain enrichment effect on small molecules, which provides a certain reference for the further development and utilization of yellow serofluid.