A method for preparing tantalum powder, comprising: 1) reducing a tantalum fluoride salt with a reducing agent in a molten diluent to obtain a raw tantalum powder, wherein said raw tantalum powder contains boron in an amount of 30-300 ppm and has a specific surface area of 5-13 m 2 /g measured by the BET method; 2) granulating said tantalum powder to obtain a pre-agglomerated powder, wherein the pre-agglomerated powder has a bulk density of 1-1.5 g/cm 3 determined according to the method specified in Standard "Metallic powders. Determination of apparent density. Part 1: Funnal method" (Standard No. GB/T1479.1-2011); wherein the granulating in step 2) comprises: mixing raw tantalum powder with water to obtain a powder mixed with water; drying the powder mixed with water to obtain a dried powder; and crushing and sieving the dried powder, wherein the mesh number of the screen for sieving is 120-170 mesh, and powder that passes through the screen is pre-agglomerated powder; 3) sequentially subjecting said pre-agglomerated powder to one or more of the following steps: heat treatment, sieving, oxygen reduction treatment, and nitrogen doping; and 4) sequentially subjecting the powder obtained in the previous step to one or more of the following steps: acid washing, water washing, drying and sieving, to obtain a tantalum powder product; wherein the tantalum powder product has an oxygen content of 10000 to 31000 ppm, a nitrogen content of 2000 to 3300 ppm; a potassium content of 10 to 50 ppm a boron content of 20 to 150 ppm; a phosphorous content of 200 to 400 ppm; wherein the tantalum powder product has a specific surface area of 5-12 m 2 /g measured by the BET method; and the ratio of the boron content of the tantalum powder product to the specific surface area of the tantalum powder product is 4-13, the boron content is measured in unit of ppm by weight, and the specific surface area is measured in unit of m 2 /g by the BET method; and wherein more than 85% of the total weight of the tantalum powder product can pass through ρ mesh, where ρ = 150. 1) reducing a tantalum fluoride salt with a reducing agent in a molten diluent to obtain a raw tantalum powder, wherein said raw tantalum powder contains boron in an amount of 30-300 ppm and has a specific surface area of 5-13 m 2 /g measured by the BET method; 2) granulating said tantalum powder to obtain a pre-agglomerated powder, wherein the pre-agglomerated powder has a bulk density of 1-1.5 g/cm 3 determined according to the method specified in Standard "Metallic powders. Determination of apparent density. Part 1: Funnal method" (Standard No. GB/T1479.1-2011); wherein the granulating in step 2) comprises: mixing raw tantalum powder with water to obtain a powder mixed with water; drying the powder mixed with water to obtain a dried powder; and crushing and sieving the dried powder, wherein the mesh number of the screen for sieving is 120-170 mesh, and powder that passes through the screen is pre-agglomerated powder; 3) sequentially subjecting said pre-agglomerated powder to one or more of the following steps: heat treatment, sieving, oxygen reduction treatment, and nitrogen doping; and 4) sequentially subjecting the powder obtained in the previous step to one or more of the following steps: acid washing, water washing, drying and sieving, to obtain a tantalum powder product; wherein the tantalum powder product has an oxygen content of 10000 to 31000 ppm, a nitrogen content of 2000 to 3300 ppm; a potassium content of 10 to 50 ppm a boron content of 20 to 150 ppm; a phosphorous content of 200 to 400 ppm; wherein the tantalum powder product has a specific surface area of 5-12 m 2 /g measured by the BET method; and the ratio of the boron content of the tantalum powder product to the specific surface area of the tantalum powder product is 4-13, the boron content is measured in unit of ppm by weight, and the specific surface area is measured in unit of m 2 /g by the BET method; and wherein more than 85% of the total weight of the tantalum powder product can pass through ρ mesh, where ρ = 150. wherein the tantalum powder product has an oxygen content of 10000 to 31000 ppm, a nitrogen content of 2000 to 3300 ppm; a potassium content of 10 to 50 ppm a boron content of 20 to 150 ppm; a phosphorous content of 200 to 400 ppm; wherein the tantalum powder product has a specific surface area of 5-12 m 2 /g measured by the BET method; and the ratio of the boron content of the tantalum powder product to the specific surface area of the tantalum powder product is 4-13, the boron content is measured in unit of ppm by weight, and the specific surface area is measured in unit of m 2 /g by the BET method; and wherein more than 85% of the total weight of the tantalum powder product can pass through ρ mesh, where ρ = 150.