The invention discloses an underground continuous wall structure with unclosed bottom planes. The underground continuous wall structure with the unclosed bottom planes comprises an underground continuous wall surrounding a to-be-excavated foundation pit, the underground continuous wall is anchored deep into a rock face and is of a closed structure formed by sequentially connecting a plurality of groove sections, the foundation bottom planes of the groove sections are designed to be planes of different elevations in accordance with the inclination design of the rock face, and a step shape in different heights is formed. According to the underground continuous wall structure with the unclosed bottom planes, existing circular underground continuous wall structure design is abandoned, the circular underground continuous wall structure with the unclosed bottom planes is adopted instead, the bottom of the underground continuous wall and the bottom of the foundation pit are in the step shapein different heights in accordance with the inclination change of the rock face, the planes of the circular underground continuous wall do not need to be structurally closed, the total excavation depth of the groove sections, the total excavation earthwork quantity of the foundation pit and total work amount of core filling are reduced, the work efficiency is improved, the work time is shortened,and thus the labor cost is reduced; and meanwhile the material consumption is reduced, so that the material cost is reduced.