Abstract: In order to screen herbicide strains with good control over common tobacco diseases and weeds, marine mangrove-derived Trichoderma sp. was isolated and purified. The isolated Trichoderma sp. strains were identified according to morphological characteristics combined with molecular biology, and their antimicrobial as well as herbicidal activities were analyzed. The results showed that there were 17 Trichoderma asperellum strains, including 3 T. harzianum strains, 2 T. hamatum strains, 2 T. reesei strains and 1 T. koningiopsis strain. Among the above 25 strains, 1 T. reesei strain (HT6), 1 T. harzianum strain (HT8), 1 T. koningiopsis strain (HT11), and 10 T. asperellum strains (HG2, HG9, HG11, HG14, HG16, 9HG, HJ3, 5HJ, HJ7, HT2) presented significant inhibitory effects on Phytophthora parasitica var. nicotianae with the inhibition rate of more than 60%; 4 T. asperellum strains (HG9, HG11, HG16, HT3) and 1 T. koningiopsis strain (HT11) had inhibition effect against Alternaria alternata (Fries) Keissler with the inhibition rate of more than 40%; 2 T. reesei strains (HT6 and HT7) possessed inhibitory activity against Ralstonia solanacearum; and 1 T. harzianum strain (HT10) had herbicidal activity against amaranth (Amaranthus retroflexus L.).