A smelting process of low-phosphorus molten steel by a low-carbon steel converter belongs to the technical field of converter steelmaking of the metallurgical industry. The process is as follows: smelting of low-carbon and low-phosphorus molten steel is realized by controlling amounts of molten iron, scrap steel, slag formers of the primary slag and the secondary slag, and the like, in the converter and by controlling bottom blowing, carbon drawing and end points. The weight percentages of the molten iron and the scrap steel in the metal charges which are put into the converter are respectively 82%-86% and 14%-18%, and the alkalinity of the primary slag and the secondary slag are respectively controlled at 1.8-2.2 and 4.0-5.0, the temperature of the molten steel is controlled at 1320-1370DEG C when making the primary slag, the temperature of the molten steel is controlled at 1650-1670 DEG C when drawing the carbon, the carbon content of the molten steel is 0.035-0.045%, the carbon content at the reblowing end point of the converter is 0.02 -0.04%, and the phosphorus content of the molten steel is controlled below 50ppm.