The invention relates to a method for preparing vanadium metal by a calcium thermal reduction of low-valent vanadium oxide, and belongs to the technical field of preparing vanadium metal powder by calcium vapor reduction of low-valent vanadium oxide. The method comprises the following steps that: the low-valent vanadium oxide and the calcium chloride are uniformly mixed to obtain a mixture, whichis cold-pressed into a block or added with water for pelletizing, and then dried to obtain molding mixture; calcium metal is added to the bottom of a reactor at 1.5-3 times mass of the molding mixture, wherein an upper layer of the calcium metal is provided with a molding mixture, and then vacuum is pumped in a cold state; a pressure in a furnace is 10<-2>-10Pa; the temperature is raised to 900-1200 DEG C at 5-15 DEG C/min; the reaction time is 2-36h; after the reaction is completed, natural cooling is performed at room temperature to obtain a block material; the obtained block material is crushed, digested with hydrochloric acid, then filtered, washed with water, washed with alcohol, dried under vacuum to obtain vanadium metal powder containing vanadium hydride; and finally, the obtainedvanadium metal powder containing vanadium hydride is subjected to vacuum sintering or smelting dehydrogenation treatment at the pressure of less than 10<-2>Pa and a temperature of 600-2000 DEG C to obtain a vanadium metal block. According to the method for preparing vanadium metal by the calcium thermal reduction of low-valent vanadium oxide, process flow is short, and energy consumption is low.