Under 10, 20 and 30sulfate wet dry conditioning cycles, crack characteristics, tensile properties of self healing products of engineered cementitious composites(ECC) specimens(curing 7, 28d) pre loaded to strain levels of 10%, 15% and 20% were investigated. The results show that ECC has good self healing effect under different cycles. The maximum width and numbers of residual crack decrease obviously. The maximum width of 7d specimens is reduced from 80μm before healing to 25μm after 10cycles. The maximum width of 28d specimens is reduced from 100μm before healing to 50μm after 30cycles. After self healing, the uniaxial tensile strain capacity of more than 67% specimens approached or exceeded the virgin specimen experienced the same cycles. Ultimate strength of 7d specimens recovered above 75% and 131% for 28d specimens. Layered CaCO3 crystals are the major self healing products.