Abstract: Phenylketonuria(PKU) was a common amino acid metabolic diseases,low-phenylalanine diet was important for PKU patients. In this study,the pearl industry byproducts-pearl oyster meat was as raw meat,and the low-phenylalanine oligopeptides were preparation by separation of proteins,pancreatin digestion,ultrafiltration grade and activated carbon adsorption separation. The results showed that with the advance of hydrolysis time,the content of <5 ku oligopeptide first increased and then decreased(p<0.05),the oligopeptide content reached the highest when hydrolysis 1 h. There was still some residual oligopeptide in the >5 ku and <300 u hydrolyzate after ultrafiltration,which >5 ku components oligopeptide content was 10.43%, <300 u component24. 52 %, while 300 u ~ 5 ku component oligopeptide content reached 68. 38 %. Phenylalanine component of<300 u component was up to 9.52%,activated carbon adsorption of aromatic amino acids were higher than other amino acids,the phenylalanine component of 300 u⁵ ku was reached 1.29% after the activated carbon adsorption. This could be used as the base material to prepare of low phenylalanine oligopeptide nutritional function products for phenylketonuria.