The invention provides a method for producing low-phosphorous molten iron by high-phosphorous reduced iron, which takes the high-phosphorous reduced iron as raw material. The method comprises: adding CaO into the high-phosphorous reduced iron, and melting and separating the CaO and the high-phosphorous reduced iron in a melting furnace at the temperature of 1400-1550 DEG C; adding dephosphorizingagents with the mass ratio into the molten iron: 30-50% of CaO, 0-10% of SiO2, 0-20% of FeO, 20-40% of Fe2O3, 5-12% of Al2O3 and 3-10% of CaF2; dephosphorizing 1-3 times at the temperature of 1300-1450 DEG C, and producing the molten iron with different phosphorus content, such as low-phosphorous and ultra-low-phosphorous high quality molten iron; therefore, the method lightens the metallurgical load of a steel refining furnace, reduces the quantity of slag, effectively develops and utilizes low grade high-phosphorous iron ore resource, and solves the problem of contradictory supply and demand of the iron ore resource at present.