The invention discloses a process of producing SPHC with low cost, short flow and high efficiency and belongs to the technical field of ferrous metallurgy processes. The process comprises the following steps of a, preparation of molten iron and waste steel; b, converter blowing: feeding the molten iron prepared in the step a into a converter by adopting a "one-ladle through" manner, and adding theprepared waste steel into the converter for blowing; c, refining outside furnace: feeding the molten steel in the converter into a steel ladle to complete the steel tapping process after smelting, rising a temperature by 8-15 DEG C on the basis of the step b while performing deoxidation treatment during steel tapping, adding a carburant, a metal deoxidizing agent, white lime and refining slag along with a steel flow, and then performing top slag recycling treatment, calcium treatment, argon blowing, ladle killing and deslagging to finally obtain refined molten steel; and d, continuous casting. For the process provided by the invention, the treatment process is shortened, consumption of an energy medium can be reduced, the cost is lowered, and indexes of a finally obtained product are easily controlled.