The invention relates to garden maintenance equipment, in particular provides a rockery water purification device. The rockery water purification device comprises a mountain body, a water purification system and a water inlet pipeline, wherein the mountain body is fixedly arranged in a fish pond; a cavity is formed in the mountain body; the water purification system is arranged in the cavity; the water purification system comprises water purification boxes, sludge tanks and a water purification tank; the water purification boxes are obliquely arranged; water filter holes are uniformly formed in the surfaces of the water purification boxes; filter plates are fixedly arranged in the water purification boxes; the water purification boxes are divided into water passing layers arranged at the upper part and water filter layers arranged at the lower parts by the filter plates; the upper parts of the water passing layers are communicated with the water inlet pipeline, and the lower parts of the water passing layers are communicated with the sludge tanks; the water filter layers are internally filled with activated carbon; the water purification tank is positioned under the water filter layers; the water purification tank is communicated with the fish pond; the sludge tanks are communicated with sewer pipes. According to the rockery water purification device provided by the invention, the layout of a garden is damaged by a water purification device arranged in an ornamental fish pond is solved, so that the rockery water purification device can be used for fish ponds in a garden.