Abstract: To isolate and screen the endophytic fungal strains that promote tobacco plants growth and improve the resistance to black shank from tobacco in different tobacco growing areas and different growth stages in Sanmenxia City, Henan Province, the endophytic fungi were isolated and cultured from tobacco roots, stems and leaves by tissue isolation method. The strains with inhibitory effect on Phytophthora nicotianae were screened using confrontation culture method and mycelial growth rate method. The strains with strong ability to produce indole-3-acetic acid (IAA) were further screened by ultraviolet spectrophotometry, after which the functional strains were identified based on sporulation morphology and gene sequence alignment. The growth-promoting ability of the functional strain on tobacco plants and the effect of prevention and control of black shank were determined using the matrix mixing bacteria method and root irrigation with fermentation broth. The results showed that 360 endophytic fungi were obtained from the roots, stems and leaves of tobacco plants in Lingbao City and Lushi County. In the preliminary screening and rescreening, the inhibition rates of 26 and 6 strains against P. nicotianae were greater than 50%, which were 50.12%-100.00% and 51.13%-92.76%, respectively. The qualitative results of IAA showed that 26 strains had different degrees of color reaction. The quantitative results showed that the IAA yield of 10 strains reached 5 mg/L. A strain, T 2#XY1, which exhibited antagonistic and growth-promoting effects was identified as Trichoderma harzianum. The total projection area, total surface area and root tip number of tobacco seedlings were significantly increased by 37.81%, 37.75% and 29.98%, respectively. It significantly promoted the growth of tobacco, and the maximum leaf length and leaf area increased by 13.05% and 15.63%, respectively. The activities of catalase (CAT), phenylalanine ammonia lyase (PAL), polyphenol oxidase (PPO) and superoxide dismutase (SOD) were increased by 108.50%, 246.99%, 40.09% and 455.87%, respectively. In addition, the content of malondialdehyde (MDA) was also significantly by 17.00%. The results of greenhouse control effect showed that the incidence and disease index of black shank were significantly reduced, with a control effect of 73.94% by root irrigation with fermentation broth of 1×10⁶ CFU/mL T 2#XY1. In summary, T 2#XY1 strain has the potential to promote tobacco growth and control black shank, offering a green approach to its prevention and control.