The invention discloses a high-acid protease yield recombinant aspergillus niger expression strain and a construction method and application thereof. The method for constructing recombinant Aspergillus expression bacteria comprises the step of constructing a recombinant expression cassette containing an acid protease gene sequence, wherein the recombinant expression cassette is a gene fragment containing the acid protease gene sequence, a promoter, a terminator, a screening marker and other components. The acid protease-producing recombinant aspergillus niger expression strain is constructed by the construction method provided by the invention. The acid protease-producing recombinant aspergillus niger expression strain is applied to production of acid proteases. Through genetic engineeringmeans, the acid protease expression cassette is constructed and is introduced into aspergillus niger expression host bacteria, so that efficient secretion and expression of the acid proteases are achieved and the high-acid protease yield aspergillus niger expression strain is obtained; and through optimization of a fermentation condition, the liquid fermentation expression level of the strain canreach 25000-26000 U/ml.