Abstract: In order to study the effects of macro fibers on the crack permeability evolution of concrete under loading, the splitting test was adopted to generate cracks on the concrete specimens. The crack permeability of different crack widths was measured in real time using the vacuum permeability test. The laser scanning equipment was adopted for the measurement of information and the reconstruction of the topography of crack surface. The effects of macro steel fiber, macro polypropylene fiber and hybrid fiber(including macro polypropylene fiber and macro steel fiber) on the crack permeability of concrete and the topography of crack surface were analyzed and compared. The results show that the macro fibers increase the crack surface roughness of concrete and indirectly decrease the crack permeability of concrete. With the increasing of fiber content, the crack permeability decreases. Compared to mono fiber reinforcement, the crack surface of hybrid fiber reinforced concrete is rough and the crack permeability of hybrid fiber reinforced concrete is small. With the increase of crack width, the crack permeability is closer to the value predicted by the Poiseuille flow model. Compared to modified factor ξ of Poiseuille flow model, parameter α of permeability is suitable for quantifying the effect of macro fibers on the crack permeability of concrete.