Provide is a method for preparing metallic titanium by electrolyzing soluble titanate with water-soluble villiaumite system molten salt. The compound fluoride molten salt containing 1% to 10% of titanate by mass is placed in a graphite crucible, the temperature is raised to 300 DEG C in a nitrogen or argon atmosphere in an airtight steel reactor, and water in the molten salt is removed at a constant temperature for 24 h; the temperature is raised to 900 DEG C to 1100 DEG C, graphite is adopted as an anode, a titanium plate is adopted as a cathode, constant-voltage electrolysis is carried out at the voltage of 3.3 V to 5.0 V, and metallic titanium powder is obtained on the surface of the cathode; and after electrolysis is finished, the cathode is lifted from the molten salt, the cathode iscooled to room temperature, cathode surface products are separated, drying is carried out after the cathode surface products are sequentially washed with deionized water, 2%-5% hydrochloric acid, 1%-5% hydrofluoric acid and deionized water, and the metallic titanium powder is obtained. According to the method, a water-soluble villiaumite system is obtained, and compared with chloride molten salt,the solubility on titanate is high, and the metallic titanium can be electrolyzed at high voltage. Compared with cryolite molten salt, wet separation of the electrolyzed titanium powder and fluorine-containing molten salt can be achieved at low temperature, operation is easy and feasible, and the work environment can be improved.