An environmentally friendly house cat scratcher with simple folding and assembling mainly comprises a first cat scratching board and a second cat scratching board. The first and second cat scratching boards have a first and second shell and a first and second clawing portion. The first and second shells have troughs. The first and second clawing portions have the clawing surface structure produced by die cutting after paper compression. Holes are provided on the clawing surface structures for clawing by house cats, and the first and second clawing portion are assembled in troughs of the first and second shell. A first junction is configured between the first shell and the second shell, and the first cat scratching board is rotated corresponding to the second cat scratching board via the first junction, enabling the first shell and the second cat scratching boards to be folded or unfolded.