The appearance of ancient brick masonry structures strengthened along the horizontal mortar joint with the random distribution short fiber reinforced Engineered Cementitious Composite （ECC） with ultra-high toughness is almost unchanged， which is consistent with the principles of repairing old heritage buildings as the old one. With different fiber types such as polyethylene fiber （PE）， polyvinyl alcohol fiber （PVA）， and hybrid fiber （PVA and PE） reinforced ECC， the content of PE fiber， caulking spacing， and single-sided or double-sided reinforcement as variables， the diagonal shear test of brick masonry under shear compression was carried out to explore the shear and the cooperative performance of brick masonry reinforced with caulking ECC. The failure pattern， load-displacement curve， shear strength， and ductility are comparatively analyzed. The test results show that caulking ECC slows down the development of internal cracks and improves the shear-bearing capacity and the integrity of brick masonry. The maximum shear strength of the reinforced specimen is increased by 44.5%， and the maximum shear stiffness of the reinforced surface is about 5 times that of the unreinforced surface.