A walking control apparatus of a robot includes a joint portion provided in each of a plurality of legs of the robot, a pose sensing unit to sense the pose of the robot, a walking state determination unit to determine a walking state from the pose of the robot, a knot point compensation value calculator to determine a Center Of Mass (COM) of the robot from the pose of the robot and to calculate a knot point compensation value, a desired angle trajectory generator to generate a reference knot point of the joint portion corresponding to the walking state, to compensate for the reference knot point using the knot point compensation value so as to generate a desired knot point, and to generate a desired angle trajectory of the joint portion using the desired knot point. The knot point which is the angle command of the joint portion of each of the legs to perform the next step is compensated for based on the COM, and the compensated desired knot point is smoothly connected using the spline curve such that the robot walks similar to a human. In addition, in order to maintain balance while walking, the angle of the joint portion of the intermediate point of the current step is fed back and the knot point of the next step is predicted and adjusted, such that the robot stably and smoothly walks.