The internal multiples are very developed in seismic data of QT area, which interfere with the effctive signal, reduce the signal-to-noise ratio and affect the imaging accuracy. In this area, the internal multiples and the primary wave are similar in the characteristics of the wave group, and the remaining time difference is small. This similarity makes it difficult for suppression. Therefore, the internal multiple has become one of the difficulties that constrain the fine exploration in this area. Based on the difference between internal multiple and primary waves, firstly, the characteristics of the internal multiple are analyzed from various aspects such as CMP gathers, velocity spectrum and stack section to determine the origin, speed and range. Then, the high-precision Radon transform method is adopted to suppress the multiples. The practical application shows that the high-precision Radon transform method gives a good suppression effect on the internal multiples in the seismic data of QT area, which has great significance to improve the imaging accuracy of seismic data in this area.