Bi1.85Mn0.15Te3 hexagonal nanoplates with a width of similar to 200 nm and a thickness of similar to 20 nm were synthesized using a solvothermal method. According to the structural characterization and compositional analysis, the Mn2+ and Mn3+ ions were found to substitute Bi3+ ions in the lattice. High-level Mn doping induces significant lattice distortion and decreases the crystal lattice by 1.07% in the a axis and 3.18% in the c axis. A high ferromagnetic state with a Curie temperature of similar to 45 K is observed in these nanoplates due to Mn2+ and Mn3+ ion doping, which is a significant progress in the field of electronics and spintronics.