The invention belongs to the technical field of building-block toys and provides a multidimensional building-block toy constructional suite with free front and back constructions, comprising first modules and second modules; the front of each module has a single short coupling post or a single row, two rows or multiple rows of first short coupling posts; the back of each first module has a concaveface having multiple rows of second short coupling posts raised. The second short coupling posts are distributed in such a way: the rows are evenly distributed in rows the same as the first short coupling posts on the front and in the middle to equally divide the adjacent rows; in the columns, each second short coupling post and the corresponding first short coupling post are alternated in the same rows of the first short coupling posts on the front and are positioned in the middle, equally dividing the two first short coupling posts. The first modules and the second modules are suitable formutual insertion. The ingenious structural design of the building-block toy constructional suite allows free constructions for the two modules in four front and back modes, and is easier to constructinto different series of toys in different designs.