A constructing method of an underwater concrete block structure, includes: a first concrete block fabrication step, a guide pole installation step, a first concrete block installation step, a second concrete block fabrication step, a second concrete block installation step, a drainage step, a guide pole removal step, and a concrete column formation step. A concrete column and a first concrete block is firmly coupled to each other via a column rebar assembly.

A constructing method of an underwater concrete block structure, includes: a first concrete block fabrication step, a guide pole installation step, a first concrete block installation step, a second concrete block fabrication step, a second concrete block installation step, a drainage step, a guide pole removal step, and a concrete column formation step. A concrete column and a first concrete block is firmly coupled to each other via a column rebar assembly.