The invention discloses a water-permeable waterway improvement spur dike, wherein one end of the spur dike is connected with a river bank, and the other end is extended into a riverbed; the spur dike is connected with the river bank in the plane to form a T shape; a dam body of the spur dike is constituted by a plurality groups of piled water-permeable frame units; each water-permeable frame unit is hollow in the middle; each group of the water-permeable frame units forms a water-permeable frame group; and a precast slab is arranged among each water-permeable frame group. By employing the piled water-permeable frames as the dam body, the invention makes full use of a slowdown and deposition promotion function of the water-permeable frame, thereby breaking a water flow structure flowing through the frame, obviously decreasing the flow rate on the bottom of the frame groups, depositing silt contained in the water, gradually silting and compacting the dam body, and forming a new bottom based on the new silt to gradually accumulate the silt. As the time goes on, the flow guiding function of the spur dike is gradually obvious. Therefore, the invention featured by high stability and good improvement effects is beneficial for draining flood in a flood period, consuming little expenses on later maintenance and decreasing engineering investment, and is convenient for promotion and application.