The invention discloses a design method for a composite structure of anti-floating anchor rod-rotary jetting body bottom sealing. The design method comprises the following steps: step1: solving the stress solution of a rotary jetting body bottom sealing plate; step2: designing the structure of anti-floating anchor rod-rotary jetting body bottom sealing; step3: determining the axial force of the anti-floating anchor rod; step4: analyzing the security of the anti-floating anchor rod-rotary jetting body bottom sealing plate. According to the damage mechanism of anti-floating anchor-rotary jetting body bottom sealing and related theories of applied elasticity, soil mechanics and foundation engineering, the design method comprehensively considers the buoyancy influence caused by the hydrostatic pressure, destructive characteristics of the anchor rod in the rotary jetting body bottom sealing plate and the cooperative work of the anti-floating anchor rod and the rotary jetting body bottom sealing plate to put forward the calculation model and the structure design theory of the structure of anti-floating anchor rod-rotary jetting body bottom sealing, thereby providing a theoretical basis for an inversed construction method and control points of the deep foundation pit in a non-precipitation operation of anchor rod-rotary jetting body bottom sealing, and the theoretical basis can be substituted to the field relevant measurement data to obtain corresponding construction parameter, and the foundation pit construction work can be carried out with the relevant construction method.