An intelligent side step apparatus for a vehicle may include a base block that is fixed to a vehicle body panel disposed at a lower end of a vehicle door, a step motor that is fixed to the base block, a driving shaft that is engaged with the step motor and is rotated by power transmitted from the step motor, a plurality of joint steps that are pivotally coupled each other in sequence, and a step operating mechanism that is coupled with the driving shaft and engaged with each of the joint steps, rotates with the driving shaft, and moves in a forward or backward direction according to rotation of the driving shaft, and wherein one of the plurality of joint steps is pivotally connected to the base block.