To explore the enrichment process of monounsaturated fatty acids from fish oil， this study used anchovy oil as raw material and purified POA using a composite solvent low-temperature crystallization method. Compared to a single solvent， composite solvents exhibited superior performance. In order to optimize the process， single-factor experiments were conducted， considering the type and volume ratio of the solvents， massratio of fish oil to solvent， crystallization temperature， and crystallization time， with POA content and yield as indicators. The optimal process conditions were determined as a volume ratio of acetone to acetonitrile of 1∶10， a mass ratio of fish oil to solvent of 1∶6， a crystallization temperature of -60 ℃， a crystallization time of 6 h， and the POA content was analyzed as (29.75±0.53)% in the obtained mixed fatty acids. Further scaling up experiments were conducted to increase the yield to around 50%， with a total unsaturated fatty acid content of over 79%. This serves as a valuable reference for the enrichment process of ω-7 monounsaturated fatty acids.