The invention relates to the field of vehicles, in particular to a leg supporting mechanism achieving four-direction adjustment through linear driving, which comprises a driving unit, a leg supporting plate, a first push rod and a second push rod, one end of the leg supporting plate is slidably connected with a U-shaped frame, and the driving unit used for driving the U-shaped frame to slide relative to the leg supporting plate is mounted between the leg supporting plate and the U-shaped frame; a first push rod and a second push rod are hinged to the two sides of the leg supporting plate respectively, a first connecting rod and a second connecting rod are hinged to the ends, away from the leg supporting plate, of the first push rod and the second push rod respectively, and a first connecting plate and a first connecting arm are hinged to the two ends of the first connecting rod respectively. The two push rods drive the connecting rod mechanism to be unfolded forwards, the cost is saved, meanwhile, in the unfolding process of the leg support, the driving device cannot interfere with the floor cross beam, meanwhile, the structural strength is greatly improved, and a motor cannot be damaged under the condition that the far end of the leg support plate is folded and loaded.