The present disclosure relates to an apparatus and a method for controlling a forklift. The apparatus and the method for controlling the forklift according to the present disclosure adjust a fork/mast inclination by referring to whether the cargo is overloaded and the forklift speeds, and particularly, when a movement direction of a cargo when the cargo slides on a fork is an outward direction, thereby preventing the cargo from falling. Further, when a degree of danger is not decreased even when a fork/mast inclination is tilted backward to the largest extent, the apparatus and the method for controlling the forklift according to the present disclosure may decrease a travelling speed of a vehicle by decreasing an output of the forklift or operating a brake, thereby remarkably decreasing the danger of the cargo falling.