Abstract: The bond strength and slip at mortar-concrete interface play a significant role in the performance of the anchor-mortar-concrete anchorage in the field of post-installation to concrete. A push-out test of mortar from concrete block can well reflect the bonding properties between mortar and concrete. But when the bond length of mortar with concrete is relatively long, the failure mode is cracking of concrete block rather than the push-out of mortar from concrete matrixes. Thus, true interfacial parameters cannot be obtained. The push-out test method is improved by locally supporting the concrete underside, which makes concrete compressed only in the local region. Hence, the concrete cracking can be avoided during the push-out process of mortar from concrete. Thus, ideal bond stress-slip curves can be given. Results show that the bond-slip curve is composed of three parts including an elastic part, a softening part and a frictional part.