The invention provides a nitryl fertilizer containing activated mineral resource humic acid and a preparation method thereof. The method comprises the following steps: mixing nitric acid with an inorganic mineral, dissolving the inorganic mineral, and separating insoluble substances to obtain an acidolysis liquid; adding mineral resource humic acid to the acidolysis liquid, adding excessive nitricacid for activation, adding alkali into the activated acidolysis liquid to neutralize residual nitric acid, evaporating and concentrating, pelletizing or milling powder, and drying to obtain the nitryl fertilizer. A composite fertilizer is prepared by adopting the mineral resource humic acid and the inorganic mineral, nitric acid is added for activation, and after activation, nitryl groups are added to humic acid molecules, to convert the mineral resource humic acid from large molecules to small molecules, and therefore, the content of humus is reduced, the contents of ulmic acid and fulvic acid are increased, the solubleness is improved, and the fertilizer efficiency is improved; the preparation method is improved on the basis of an original process, without increasing a too complex production line, and thus has the advantages of being convenient, simple, and easy for production.