The invention provides a construction method of the vertical construction joint of a bare concrete facing and relates to the technical field of on-site fabrication of building materials or building components. The construction method of the vertical construction joint of the bare concrete facing aims at solving the problem of poor building integral impression due to exposure of joints in walls, serious grout leakage and nonstraightness of the joints in existing processing technologies of the vertical construction joints of bare concrete facings. The method includes, firstly establishing a wall formwork, setting vertical splitting bars on the facing of a bare concrete wall I, removing the formwork after concrete is poured and reserving formwork end joints; secondly, removing the vertical splitting bars and the formwork end joints, digging out a bar-shaped block from the surface layer of the wall between the vertical construction joints and grooves formed in the facing of the bare concrete wall I; thirdly, re-embedding the vertical splitting bars into the grooves, establishing the formwork of a bare concrete wall II, pouring concrete into the formwork and removing the formwork and the vertical splitting bars to obtain the bare concrete wall II connected with the bare concrete wall I.