The invention discloses a close-loop simulation-based distributed load optimization design method for a carrier. The method comprises the steps of firstly building a six-degree-of-freedom dynamics model for the carrier, then performing close-loop simulation to obtain dynamics parameters, building a distributed load shear force calculation model, a bending moment calculation model and an axial force calculation model of the carrier, and calculating lower section shear force, lower section bending moment and section axial force of each site of the carrier; and secondly, rechecking the situation on whether loads of the carrier meet the requirements or not, if the loads of the carrier meet the requirements, ending the design, if the loads of the carrier do not meet the requirements, optimizing a close-loop simulation input, re-obtaining the dynamics parameters, and calculating the lower section shear force, the lower section bending moment and the section axial force of each site, until the loads of the carrier meet the requirements. According to the method, the loads on all the sections of the carrier of a rocket in a flight process can be really reflected; and therefore, the method is of great significance for rechecking the completeness and design margin of load design.