New discovery of oil and gas in the flank of Balingshan-Huayuan anticline structure in the recent years makes it necessary to have a further understanding of its structural nature. Based on the interpretation of seismic profiles, it is considered that K2 y-Ex is the superimposition of salt and mud tectonics, and can be divided into salt dome-salt pillar multi-layered superimposed structure, salt mud dome-salt mud pillar structure and salt mud dome structure. The formation of salt mud tectonics was the superposition effect of plasticized salt mud stone bedding creep which led to thickening of the single layer and the multi-layer accumulation. Reverse fault was formed by the salt mud intrusion along the early hanging wall of fault and the diapirism, thus the fault had the characteristics of the upper bed showing reverse and the lower showing normal. Differential loading and volcanic thermal convection were the dominant dynamic mechanisms.