Tetrahydro-beta-carbolines (THBCs) are important structural units of indole alkaloids, most of which have significant biological properties, such as anti-inflammatory, antiviral, anticancer, antibacterial, and antioxidant properties. Herein, a Pictet-Spengler oxidation reaction with 3-(2-methylaminoethyl) indole and alcohols as starting materials was developed over the pincer manganese catalyst. The reaction system showed good substrate applicability, 12 kinds of THBC products were synthesized from aromatic alcohols and aliphatic alcohols with the yields of 43%similar to 99%. The structures of the products were confirmed and characterized by H-1 NMR, C-13 NMR, IR and HRMS. The antioxidant activity of these compounds were investigated by scavenging ABTS(+)center dot and DPPH center dot. The results showed that in the two test systems, all of those compounds had good free radical scavenging ability, indicating that those compounds are a class of potential antioxidant. Among them, 1-(4-fluoro-phenyl)2-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (3c), 2-methyl-1-(naphthalen-2-yl)-2,3,4,9-tetrahydro-1H-pyrido-[3,4-b]indole (3e), 2-methyl-1-propyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole(3h), 2-methyl-1-propyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (3j) and 2-methyl-1-(2-(pyridin-3-yl)ethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (3l) showed the best effect on scavenging ABTS(+)center dot, while 1-cyclohexyl-2-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (3i) and 2-methyl-1-(2-(thiophen-2-yl)ethyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (3k) were slightly weaker, followed by 2-methyl-1-phe-nyl2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (3a), 2- methyl-1-(4-(methylthio)phenyl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]-indole (3b), 1-(furan-2-yl)-2-methyl-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (3d), 2-methyl-1-(pyridin-3-yl)-2,3,4,9- tetrahydro-1H-pyrido[3,4-b]indole (3f) and 2-methyl-1-(thiophen-2-yl)-2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole (3g), and IC50 could reach 0.073 mg center dot mL(-1) or above. Among of the target compounds, 3a, 3c, 3e and 3h had the best effect on scavenging DPPH center dot, followed by 3d, 3i, 3j and 3l, and 3b, 3f and 3g had the worst effect. In conclusion, compounds 3c, 3e and 3h had good scavenging ability on ABTS(+)center dot and DPPH center dot, while compounds 3b, 3f and 3g had poor scavenging ability on 2,2 '-azinobis(3-ethylbenzothiazoline-6-sulfonate) cationic radical (ABTS(+)center dot) and 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH center dot).