The invention belongs to the field of composite materials, and relates to a preparation method for a sulfonated coal composite material capable of enriching lanthanum ions in tailing wastewater. The preparation method comprises the step that modified sulfonated coal is composited into hole channels of ammoniated sunflower stalks and comprises the specific processes of sunflower stalk washing, ammoniating, sulfonated coal modifying, composite material preparing and the like. Compared with the sunflower stalks, the composite material has the advantages that the saturated enriching quantity of the lanthanum ions is significantly increased, and overflowing pollution of sunflower stalk organic carbon in the water treating process can be avoided. The prepared composite material increases the enriching quantity of the lanthanum ions to 91.9 mg/g, can be applied to lanthanum-containing tailing wastewater treatment and is wide in market prospect.