Titanium is an important strategic commercial metal. At present, the titanium industry is based on the high-energy Kroll process. At present, electrochemical methods and metal thermal reduction methods have different degrees of difficulty in preparing elemental titanium.There is a technical bottleneck in the preparation of metallic titanium powder by conventional thermal reduction of TiO₂ with calcium, magnesium, or other metals, such as low efficiency and incomplete deoxidation. Based on the thermodynamic equilibrium characteristics of the step-by-step reduction of TiO₂, a comparative study method was used, and the thermodynamic and kinetic differences between magnesia and calcium heat reduction of TiO₂ were investigated in this paper. Considering the difference in the electronegativity between magnesium and calcium, a new idea was put forward that the primary reduction product is prepared through a primary reduction process of TiO₂ in the form of magnesiothermic self–propagation high–temperature synthesis (SHS), and then the reduced titanium powder is obtained through the primary reduction product for a deep calcium-thermal reduction reaction. The reduction degree and mechanism of TiO₂ during the primary magnesium thermal reaction and deoxidation mechanism of primary reduction products in different deep reduction modes were investigated in this paper. The results showed that it is more conducive to undergo complete deoxygenation such that the primary reduction product is first acid-impregnated followed by deep calciothermic reduction. High purity reduced titanium powder with a final oxygen content of only 0.21% and purity greater than 99.0% was obtained.