The invention relates to a fish pond fitting, in particular to an automatic dredging type fish pond drain valve. The drain valve consists of a pull ring, a dredging needle, a front tube, a pushing spring, a rotary fin, a tail tube, a valve shell, a knob, a valve core, a reset spring, a valve shell hole, a valve core hole, a magnet, a front snap ring, a central snap ring and a tail snap ring, wherein the valve shell is hollow sphere-shaped; the valve core is positioned in the valve shell and is in movable fit with the valve shell; the dredging needle, the rotary fin and the magnet together form a dredging rod; one end of the dredging needle is provided with the pull ring which is connected with the dredging needle, the central part of the dredging needle is provided with the rotary fin which is integrated with the dredging needle, and the other end of the dredging needle is segment-shaped; and a disc-shaped magnet is glued to a plane end of a segment. The automatic dredging type fish pond drain valve can greatly improve the drainage efficiency of the fish pond and reduce the probability of blockage of drainage pipelines.