The invention provides a chickpea oligopeptide and a preparation method thereof. The preparation method comprises the following steps: mixing chickpea powder with water, regulating the pH value to 8-10, stirring, centrifuging, and collecting the supernate; regulating the pH value of the supernate to 4-6, stirring, centrifuging, mixing the precipitate with water, stirring, centrifuging and collecting the precipitate to obtain the chickpea protein; preparing the chickpea protein into a protein solution with the pH value of 8-10, and adding an alkaline proteinase to obtain a first enzymolysis solution; regulating the pH value of the first enzymolysis solution to 6-8, adding a neutral proteinase and a flavor proteinase, and inactivating the enzymes to obtain an oligopeptide crude solution; and filtering the oligopeptide crude solution through a ceramic membrane, concentrating, decolorizing, and drying to obtain the chickpea oligopeptide. The preparation method has the advantages of accessible raw material, simple technique and high yield. The mass content of peptides with the molecular weight of less than 1000Da in the prepared chickpea oligopeptide is greater than or equal to 90%, and the mass content of the oligopeptide is greater than or equal to 75%.