The meat of Pinctada martensii,which is rich in protein,is the aquatic low-value byproduct.In this study,a high Fischer ratio oligopeptides mixture(PHFP) was obtained using gel filtration chromatography combined with activated carbon adsorption from pancreatin hydrolysate.The PHFP was separated by HPLC,the molecular weight distribution of PHFP and separated fractions were analyzed by ESI-MS,and the amino acids compositions were further studied.The results indicated that the molecular weight distribution of PHFP was between 150~1000 u,among the three separated fractions-PHFPa,PHFPb and PHFPc,the content of BCAA in PHFPb and PHFPc increased to 30.2% and 29.5%.The content of PHFPa,PHFPb and PHFPc in total PHFP is 41.3%,38.8% and 19.7% respectively in this study.