The invention relates to a fire-refining method of crude bismuth, and belongs to the technical field of fire metallurgy. The fire-refining method comprises the following steps: liquating a crude-bismuth melt so as to remove copper; performing vacuum distillation again on the liquated crude-bismuth melt so as to remove impurities, such as lead and silver; performing chlorination refining; and finally performing refining so as to obtain refined bismuth. According to the fire-refining method disclosed by the invention, a vacuum distillation technique is adopted for replacing a procedure that zinc is added in a refining kettle so as to remove silver, and partial lead, antimony, tellurium and arsenic are removed, so that the labor strength of workers is reduced; through secondary vacuum distillation, crude silver with a high silver content can be directly collected in a vacuum furnace, and generated secondary crude bismuth can be recycled, so that the cost is greatly reduced; a subsequent zinc removing procedure is also omitted, and the amount of chlorine gas for subsequent chlorination refining is greatly reduced, so that harm to environment is reduced to a great extent, and the direct recovery rate of bismuth is increased; the whole technological process is safe and controllable, the operation is convenient, adopted equipment is simple, the universality of raw materials is high, the direct recovery rate of bismuth is high, and the slag yield is low.