The invention discloses an ignition method for producing nitric acid through an ammonia oxidation process. The ignition method comprises the following steps: setting a normal ammonia and air ratio value in a ratio controller to be the molar content being 9.5-10.5 percent, and setting an ammonia and air ratio interlocking value to be the molar content being 11 percent; and setting the automatic gradual-change mode of an ammonia flow regulating valve to be characterized in that the ammonia/air ratio reaches the molar content being 8.5 percent in 2.0-2.5 minutes by DCS, wherein the ratio molar content is increased from 0 percent to 7 percent in the first 2 minutes, the molar content is increased from 7 percent to 8.5 percent within 1 minute, and the ammonia/air ratio is adjusted to be the molar content being 9.5 percent within 5 minutes. The ignition method disclosed by the invention has the advantages that the nitric acid feeding ignition safety requirement is met, and the environmental pollution is avoided.