The invention discloses a process method for concentrating soybean peptides by adopting serial membranes. Firstly, an alkali solution of 
soybean protein isolate is prepared, and Alcalase 
protease is added to the alkali solution of 
soybean protein isolate, and the 
enzyme is deactivated after 
enzymatic hydrolysis, and the supernatant obtained by 
centrifugation is crude soybean  
Peptide liquid; the crude soybean 
peptide liquid is subjected to total 
reflux nanofiltration operation at 
room temperature, and the adsorption and deodorization of 
activated carbon is carried out at the same time as the 
nanofiltration operation. The 
nanofiltration operation uses 6 nanofiltration membranes in series, and the molecular weight 
cut-off is 150Da~  2000Da, pressure 0.2MPa ~ 1.0MPa, treatment for 5 ~ 20min to remove inorganic salt ions with a relative molecular 
mass ≤ 150Da, collect and filter out the soybean 
peptide mixture; spray dry to obtain soybean 
peptide.  The present invention adopts six nanofiltration membranes to process in series to increase the 
dry matter content of the material, reduce the cost and shorten the 
production cycle; at the same time, it performs adsorption, deodorization and debittering of 
activated carbon, completely removes the peculiar smell of soybean peptide and keeps the soybean peptide mixture clear and transparent.