The invention relates to a method for preparing titanium deuteride by a high-temperature direct process, belonging to the cross fields of material science and nuclear science. Metal titanium and deuterium gas react at high temperature to generate the titanium deuteride. The method solves the problems of titanium deuteride industrial-scale preparation technique and preparation purity, does not need complex production devices, only needs simple and accessible preparation devices, and thus, can implement safe construction of the titanium deuteride production line under existing plant conditions. The preparation technique is simple and easy to operate, does not need any high-temperature pressurizing or depressurizing device in the preparation process, and is safe and reliable under the protection of inert gas. The product has the advantages of favorable yield, favorable purity and high stability, and can be stored for a long time. The method does not generate three wastes in the production process, is harmless to the human body and environment, is environment-friendly and green, and thus, has important meanings for industrial large-scale safe preparation of high-purity titanium deuteride and large-scale application thereof.