The utility model discloses a highway subgrade protection system, including the road bed main part, the road bed main part comprises rail guard device, side slope antiskid, guard plate, drainage device, the both sides of road bed are provided with side slope antiskid, be through concrete fixed connection between side slope antiskid's spill body and the road bed, side slope antiskid passes through the stock and connects in the road bed, be equipped with drainage device between side slope antiskid and the road bed, one side of drainage device is provided with the guard plate, and the both sides face of road bed is provided with the rail guard device, is provided with the greenbelt on the rail guard of rail guard device, through setting up drainage device, rail guard device, the problem that the surface gathered water discharged has been solved, the simple effectual surface gathered water of having handled to and after having utilized drainage device's processing, convenient and fast's solution the irrigation work of the greenbelt on the rail guard device.