The invention relates to an acid injecting device of a nitric acid storage tank and a control circuit of the acid injecting device. The acid injecting device comprises a corrosion-resistant self-sucking pump (3), wherein the corrosion-resistant self-sucking pump (3) is communicated with an acid injecting pipe orifice (1) through an input pipeline and communicated with the nitric acid storage tank (10) through an output pipeline; a pump inlet ball valve (2) and a pump outlet ball valve (4) are connected to the input pipeline and the output pipeline respectively; and a nitric acid storage tank acid inlet (8) is positioned on the top part of the nitric acid storage tank (10). Because the nitric acid storage tank acid inlet is formed on the top part of the nitric acid storage tank, the working pressure during work and the static pressure during standby of the pipelines are reduced so that the acid injecting process is safer.