Objective To investigate the nitrogenous chemical constituents of Weiceng .Methods Weiceng extract was subjected to various column chromatography and spectroscopic methods were used for the elucidation of compounds .Results Seventeen compounds were isolated and identified as cyclo-(Leu-Tyr)(1), cyclo-(Phe-Tyr) (2), cyclo-(Pro-Gly) (3), L-Pyroglutamic acid methyl ester (4), uracil (5), thymine (6), N-acetylphenylalanine (7), tyrosine (8), phenylala-nine (9), phenylalanine methyl ester (10), N-methyl leucine (11), isoleucine (12), valine (13), leucine (14), glutamic acid (15), glycine (16) and aspartic acid (17).Conclusion All the seventeen compounds are isolated from Weiceng for the first time .Before this study , cyclopeptides 1-3 have never been isolated from soy bean or its products .