How the ancient landslide developed in Pingpo Village in the middle reaches of the Lancang River (LR) is controlled by faults and its impact on river channel changes is related to the selection of major bridge sites and engineering structures crossing the river section. Although the controlling effect of faults on landslides is well known, their profile changes and the impact on the eastward migration of the Lancang River's curved channel are not clear. On the basis of previous research, the geological structure and its sediment changed with depth and crossing river valleys were explored by deploying high-density electrical methods and magnetotelluric profiles that span a total length of 3.36 km across the river channel. The results showed the spatial distribution of faults on both sides of the river, their impact on the eastward bending of the river channel, the structural characteristics of residual landslide, changes in buried ancient river channels, and the characteristics of modern riverbed deposits such as thicker upstream than downstream and larger on the right bank than on the left bank, which were affected by the NNE sliding of ancient landslides without underlying controlling faults. The geological conditions revealed by the four boreholes crossing the river are consistent with the geophysical results, further verifying the impact of ancient landslides on the eastward movement of the Pingpo section of the river by 350 m and the thickness changes of the box shaped riverbed and sediment on both sides. The internal structural characteristics of the residual body of the landslide are sliding diagonally towards the opposite bank and the protruding bedrock on the riverfront edge. Compared with the satellite remote sensing impact in 1985, the latest landslide was found to be inclined towards the NNE direction of the upper reaches of the LR, rather than two parallel landslides as previously stated. The research results provide a reference for understanding the abrupt changes in river direction controlled by fault structures and the influence of ancient landslide pushing, as well as the development characteristics of ancient landslides along the river, which playing roles for bridge sitting and engineering structure selection.