When the normal pulse signal excited ultrasonic wave was used to detect the pipeline defects, there was a limitation that the average transmitted sound power was small and the band of detection signal was single, and it was also very difficult to determine the emission source of echoes and calculate the acoustic characteristic parameters of the whole sound field in the tested body in the case of the array detection with multiemission and multireceive. Therefore, a binary ultrasonic coding method using sine wave frequency modulation to detect pipeline defects was proposed in this paper. The mathematical model of the coding excitation response of the sensor is established. The amplitudefrequency response of the sensor under different excitation frequencies, fractional bandwidths and code bits is obtained by simulation. The received signal is distinguished and the transmitted sound source is identified effectively. Finally, the method is applied to the ultrasonic testing of pipeline defects, and the effective detection of different kinds of pipeline defects and effective identifications of emission sources are realized. The sensitivity of the defects to different frequency bands in binary coded excitation mode is also analyzed. The statistical results show that the detection rate of 2~4 bit code for pipeline leakage holes and crack defects is higher than 62%, and the correct rate of echo signal identification is higher than 97%.