To investigate the shear behavior of Load-bearing Horizontal-hole Interlock Concrete Block (LB-HHICB），three kinds of blocks were used to fabricate the shearing specimens and each took three mortar strengths as variables. At first, a static shear loading test was carried out to investigate the failure profiles and shear failure loads of the specimens. Then, the main factors affecting the shear strength of the masonry were analyzed and compared with other similar test results and specification values. Finally, a method was proposed to calculate the shear strength of LB-HHICHB considering the effective bonding area. The study showed that the shear failure of LB-HHICB was mainly bond failure of the interface between mortar and concrete block. When calculating the shear strength of masonry, the effective bonding area between mortar and concrete block was employed. Based on it, the calculation method on shear strength of LB-HHICB was put forward. This calculation method can not only accurately calculate the shear strength of this kind of block but also calculate the other types of concrete block based on the shear bond failure.