The invention discloses a single-motor biped robot. The single-motor biped robot comprises a robot body and leg plates vertically arranged on the left portion and the right portion of the robot body correspondingly. A double-end direct current speed reduction motor is mounted on a front side plate face of the robot body. Rotating wheels are coaxially and fixedly mounted at the shaft ends of outputshafts of the double-end direct current speed reduction motor correspondingly, and each rotating wheel is in eccentric rotating connection with the leg plate on the corresponding side through an eccentric rotating shaft. A long groove is formed in the top of each leg plate in a vertically-downward mode. A spindle with the center axis in the left-right horizontal direction is rotationally mountedon the upper portion of the front side plate face of the robot body, the left and right ends of the spindle penetrate through the long grooves of the leg plates on the corresponding sides, and the shaft ends of the spindle and the long grooves where the shaft ends are located are in relative rotating and sliding fit. A control box and a battery box are arranged on a rear side plate face of the robot body, wherein the control box is internally provided with a speed reduction motor circuit, and a power supply battery in the battery box supplies power to the double-end direct current speed reduction motor through the speed reduction motor circuit. The movement stability of the robot is improved, and the single-motor biped robot has the advantages of low cost and concise structure.