Abstract: The umani components of 4 representative retail lobster sauce products were studied by ultrafiltration membranes separation, combinated taste dilution analysis with sensory evaluation. The studies showed that the umani components of Yangjiang and Guizhou water lobster sauce were prominent in samples and free amino acid was not the main umani conposition of Yangjiang lobster sauce. The molecular weight at 1 ~ 3ku ultrafiltration components had obvious umani flavor even in 0. 25g/L concentrations, which showed that the main uamni components of Yangjiang lobster sauce were between 1 ~ 3ku peptide.