The invention discloses a side hole punching die of a U-shaped guide rod base of an automobile driving axle. The side hole punching die comprises an upper die body and a lower die body, and is characterized in that the upper die body comprises a die handle, an upper die plate, a male die base plate, a male die fixing plate, a punching male die, side edge unloading rubber, middle unloading rubber and an unloading plate, the die handle, the upper die plate, the male die base plate, the male die fixing plate, the punching male die, the side edge unloading rubber, the middle unloading rubber and the unloading plate are sequentially fastened and connected from top to bottom, the lower die body comprises a punching female die, a female die fixing plate, a female die fixing plate inner guide sleeve, a female die fixing plate inner guiding column, a female die fixing plate supporting spring and a lower die plate, the punching female die, the female die fixing plate, the female die fixing plate inner guide sleeve, the female die fixing plate inner guiding column, the female die fixing plate supporting spring and the lower die plate are sequentially fastened and connected from top to bottom, the middles of the left side edge and the right side edge of the female die fixing plate are respectively provided with a side edge locating block, and the female die fixing plate is connected with the lower die plate through the female die fixing plate supporting spring. The punching process is stable, deformation is avoided, and it is accordingly guaranteed that the concentricity of side holes in the two edges is stable.