Abstract: Volume ratios（0,1%, 1.5%, 2%） of steel fiber and the layers（0,3,5,7） of PET fiber grille were adopted to pouring PET fiber grille/steel fiber reinforced high strength concrete specimens, the volume ratio of steel fiber and the number of grille layers and their effects on the mechanical properties of high strength concrete were studied, and the hybrid effect of steel fiber and PET fiber grille, the Interfacial Microstructures between concrete matrix and steel fiber and the Interfacial Microstructures between concrete matrix and concrete matrix were analyzed. The results show that PET fiber Grille is beneficial to the increase of flexural strength of concrete and is bad to compressive strength, while steel fiber is beneficial to the compressive strength and flexural strength of concrete. When steel fiber and PET fiber grille are mixed in concrete, the effect of hybrid strengthening of flexural strength is not obvious, but the effect of hybrid compressive strength shows obvious compensatory effect.