Based on the carbamoyl triazole herbicide Cafenstrole, 12 novel selenium-containing compounds were designed and synthesized. All of the compounds were characterized and confirmed by IR, 1H NMR, and high-resolution mass spectroscopy. The bioassay tests showed that some of the compounds (C2, C4, C(7-8), and C12) exhibited good inhibitory activity against cucumber (Cucumis sativus L.) and semen euphorbiae (Leptochloa chinensis N.). Especially, compound C6 inhibited the growth of cucumber and semen euphorbiae by >90% at a concentration of 1.875 microg/mL, and the inhibition of the compound on the rice (Oryza sativa L.) was only 8.3% at a concentration of 7.5 microg/mL, which indicated a higher selectivity between weed and rice than that shown by Cafenstrole.