Abstract: In order to investigate the influence law of steel fiber content on the mechanical behavior of alkali slag concrete, the steel fiber alkali-activated slag concrete stress performance test specimen for a total of 54 were made, the cube compressive strength, prism compressive strength, elastic modulus and Poisson's ratio test and research were performed, and the qualitative and quantitative analysis of specimen internal micro cracks were given to reveal the steel fiber to enhance toughening mechanism of alkali slag concrete.The results showed that the theoretical calculated values of the steel fiber content related cube compressive strength correction formula were in good agreement with the results obtained in the experiment; In a certain range, the steel fiber content can improve the strength, elastic modulus and Poisson's ratio of the material. Too much content of steel fiber content would cause the phenomenon of agglomeration inside the concrete material, increase the interfacial transition zone and reduce its mechanical properties. The optimum steel fiber content under the ratio of alkali-activated slag concrete is 1.4%.