An apparatus for controlling shifting of a vehicle and a method therefor are provided, where the apparatus includes a storage storing a power map in which a demand power corresponding to a vehicle speed and an accelerator position sensor (APS) value is recorded and storing an energy consumption map of a power source for each gear stage. The apparatus includes a controller that detects a current demand power based on the power map, generates a power graph representing the detected demand power as the number of revolution and a torque of the power source for each gear stage, and matches the generated power graph with the energy consumption map of the power source to control a shift to a gear stage which consumes minimum energy.