To study the secondary metabolties of Streptomyces sp. KC17012.The compounds were isolated by silica column chromatography,Sephadex LH-20 column chromatography,and RP-18 reverse-phase column chromatography from the EtOAc extract of the culture of Streptomyces sp. KC17012.The structures were characterized by various spectroscopic method (¹H NMR,¹³C NMR and MS) and comparison with the data of literatures.Eighteen compounds were isolated from the EtOAc extract,and identified as seco-((S)-Pro-(R)-Val) (1),cyclo(L-Pro-L-Tyr) (2),cyclo(D-Pro-L-Tyr) (3),cyclo(L-Pro-L-Phe) (4),tryptophan (5),methyldioxindole 3-acetate (6),1H-indole-3-carboxylic (7),anthranllic acid (8),thymidine (9),macrolactin A (10),carthamate A (11),(-)-methyl dihydrophaseate (12),phaseic acid (13),(-) -ethyl dihydrophaseate (14),blumenol A (15),3α-hydroxy-5α,6α-epoxy-7-megastigmen-9-one (16),trogopterin A (17),and β-sitosterol (18).All compounds were isolated from Streptomyces sp.KC17012 for the first time,compounds 1-4 were dipeptide type compound,and abscisic derivatives (11-14) belong to sesquiterpenes.Microdilution method was used to test the antibacterial activity of the above compounds.Compounds 1 and 10 were effective against Bacillus subtilis,Escherichia coli,and Staphylococcus aureus at the concentrations of 11 and 33 μmol/L respectively.This study lay a foundation for the further exploitation of the metabolites of Streptomyces sp. KC17012.