The invention relates to an ecological interlocking block and an ecological interlocking block type slope protection construction method. The ecological interlocking block comprises a block body; the left side and the right side of the block body are symmetrically provided with wedge-shaped mortises; the front side and the rear side of the block body are symmetrically provided with connecting grooves; the interior of the block body is provided with two through holes. The ecological interlocking block type slope protection construction method particularly comprises the following steps of slope levelling processing, pavement of composite geo-membrane, pouring of C20 plain concrete foundation, pavement of ecological interlocking brick, coping of concrete capping and construction of slope top. The ecological interlocking block type slope protection construction method has the advantages that every interlocking brick block and the adjacent six interlocking brick blocks generate super-strong connecting functions and the integral stability is high under washing through river water; the slope protection durability and stability is improved along with growing of plants in central holes of the interlocking bricks, a function of protecting river ecological environment is achieved; slope protection, ecological restoration and decoration are integrated, the structure is stable and economic, and the construction is convenient, and the ecological interlocking block type slope protection construction method can be applied to treatment engineering of medium or small rivers.