Chemical huff-puff agent of thickened oil, as well as preparation method and application of chemical huff-puff agent

The invention provides a chemical huff-puff agent of thickened oil, as well as a preparation method and an application of the chemical huff-puff agent. The huff-puff agent comprises a main agent A and an adjuvant B at a mass ratio of 1:1, wherein the main agent A comprises biuret, sodium nitrite, ammonium chloride and diphenylbenzidine at a mass ratio of (6-8):(4-6):(4-6):(2-4), and the adjuvant B comprises dodecyl sulfonate, oxalic acid, dimethyl polysiloxane, imidazoline and sodium dodecyl sulfate at a mass ratio of (7-9):(5-7):(1-3):(2-4):(1-4). The invention further provides the preparation method of the huff-puff agent, and the application of the huff-puff agent in thickened oil recovery. The chemical huff-puff agent of the thickened oil can remove various blocking generated in each link of an oil well when applied to the thickened oil recovery; under the condition of an oil layer, stratum energy can be supplemented; mining speed and recovery percentage are increased; mobility of crude oil is improved; flow resistance is reduced; and the purpose of yield increase of a low production well is realized.