The invention discloses a potato seedling silage header and a self-propelled potato seedling silage harvester. The potato seedling silage header comprises a floating frame connected with a frame, andthe floating frame is capable of floating up and down to realize height adjustment and fixedly connected with a reel assembly. Lateral reciprocating cutters are arranged on the lateral side of the frame and used for cutting off potato seedlings in potato ridges. A screw conveying roller is arranged on the rear side of the reel assembly, and bottom reciprocating cutters are arranged under the frontof the screw conveying roller and used for cutting off roots of the potato seedlings. The reel assembly comprises a frame body, a plurality of elastic tooth shafts are hinged to the frame body and fixedly provided with a plurality of elastic teeth, the end of each elastic tooth shaft is connected with a guide rod through a connecting rod, and the end of each guide rod is positioned in a guide rail in a disc structure and capable of sliding along the slide rail.