The invention discloses a low-nitrogen boron-containing steel smelting method for improving the boron element yield. Converter end point boiling tapping is conducted, the frequency that molten steel absorbs nitrogen from air is reduced, a slag modifier and lime are added after converter tapping is finished for adjusting slag oxygen potentials and components, and in the tapping process, a steel ladle is subjected to bottom blowing and stirring in the whole process; after tapping is finished, molten steel is conveyed to be subjected to RH treatment, after the steel ladle is conveyed in place, vacuum pumping is conducted, C in the molten steel is utilized for deoxygenation, and after the oxygen content is reduced to be 0.02% or below, aluminum is added for deoxygenation and alloying, the 1.0-3.5 kg/t of slag modifier is added in the slag face of the steel ladle, and after all the alloy and the slag modifier are added, clean circulation is conducted for 5 min or longer time, T.O in the molten steel is smaller than or equal to 0.002%, the steel slag T.Fe+MnO is smaller than or equal to 2.0%; then, a boron-iron alloy is added, clean circulation is conducted for 8 min or longer time, andvacuum breaking and tapping are conducted. During RH tapping, the boron yield reaches 89% or above, the content and the yield of the boron element in the molten steel are stably controlled, BN precipitation in the later continuous casting process can be reduced, and important significance is achieved for stabilizing the mass and performance of the boron containing steel.