In this paper, an ultrasonic-based localization using ultrasonic reflection method is proposed. Experiment environment includes a mobile robot and four poles forming a square around the measuring site. Ultrasonic sensors built on the poles serve as receivers and the mobile robot serves as a transmitter, and all ultrasonic sensors are integrated with their Zig-Bee modules. By the sequential ultrasonic signal transmission between the robot and the poles, the ultrasonic sensors on the poles can then measure the time-of-flight (TOF) without interference to calculate the distance between the receiver and transmitter ends. According to an established twodimensional coordinate model, position of the robot can be obtained based on the distance measurements. Thanks to Zig-Bee modules, position information of the robot can be instantly conveyed to a remote PC for monitoring the robot and path planning. Extensive experiments conducted have shown a satisfactory accuracy of the coordinates of the mobile robot can be obtained via the proposed localization scheme.