Abstract: The use of GPS ionospheric tomography to detect the ionosphere has been developed for decades, particularly during the period of ionospheric storms. In this paper, a multi-resolution tomographic algorithm based on GPS data is proposed to reconstruct the ionosphere over the eastern and western USA on March 16-17, 2015. First, the accuracy of inversions using the multi-resolution tomographic algorithm is analyzed by comparing with independent ionosonde data. It is confirmed the feasibility of the multi-resolution tomographic algorithm during the magnetic storm period. Secondly, the occurrence of a large-scale travelling ionospheric disturbance (LSTID) caused by the ionospheric storm is verified from the reconstructed ionospheric images in the eastern USA on March 17, 2015. The horizontal characteristic ofthis LSTID is also discussed with inverted TEC estimates. Finally, the vertical feature of the LSTID is studied by comparing the inverted electron density profile and the incoherent scatter radar (ISR) scan. The results show that the wavelength of LSTID is about 1 200 km, the period is 50-60 min, and it propagates to the southwest direction at a wave speed of 350-400 m/s, and the accuracy of the vertical electron density of the TID is reliable.