In this article, we propose a delayed reference generation method for a humanoid to stably imitate human walking. An admissible condition for a robust imitation is first defined from the state of the robot and the target support polygon. In addition, a motion buffer is proposed and implemented to apply a time delay to the human motion according to the abovementioned condition for use as a reference to the robot. A data acquisition device and the HUBO2+ humanoid platform were used in teleoperation experiments to verify the effectiveness of the proposed method. We confirmed that the robot could stably imitate human footsteps under either static or dynamic walking when applying the proposed method.