The invention provides a rockfill dam downstream dam surface slope protecting structure. The structure comprises a downstream dam surface of a rockfill dam, longitudinal reinforced concrete flower beds and transverse reinforced concrete flower beds staggered on the downstream dam surface in a latticed mode, dry block stone layers paved in the areas, without the longitudinal reinforced concrete flower beds and the transverse reinforced concrete flower beds, of the downstream dam surface, a spray irrigating system, and a draining and reverse filtering system, wherein the longitudinal reinforcedconcrete flower beds extend in the dam axis direction, and are filled with cultivating soil and planted with climbing plants; and the transverse reinforced concrete flower beds extend in a direction perpendicular to the dam axis, and are filled with the cultivating soil and planted with shrubs, flowers and plants. Under the condition of adopting the dry block stone layers to protect slopes, the structure can realize the afforestation of the whole downstream dam surface through the longitudinal reinforced concrete flower beds and the transverse reinforced concrete flower beds staggered in the latticed mode.