A method for eliminating misjudgment of a reflective light is provided. A light source emits a transverse linear light toward a direction of a floor as detection light and the light sensor senses reflective light signals from an object that reflects the detection light. In the method, a frame image including the reflective light signals is captured by the light sensor, centers of gravity of the reflective light signals are analyzed, and the centers of gravity of the reflective light signals can be corrected based on a line of gravity or a center of gravity of previous reflective light signals stored in a memory of the autonomous robot in order to exclude a center of gravity generated by the reflective light signal from a wall. A distance of the object can be confirmed based on the corrected centers of gravity of reflective light signals.