Thorium is a possible nuclear fuel to achieve the sustainable development of nuclear energy. The molten salt reactor (MSR) has great potential and advantages in realizing the efficient utilization of thorium resources. However, there are still many challenging technologies to be developed, such as the graphite lifetime problem, the complex online processing of the fuel salt. Therefore, the actual deployment timelines of thorium‐based MSR are still unpredictable. In this research, a Thorium‐based Molten Salt Fast Energy Amplifier (TMSFEA), which is based on the subcritical chloride salt fast reactor, is proposed. It adopts a single‐fluid, moderator‐free simple core design. A ternary molten salt system containing sodium chloride (NaCl), thorium tetrachloride (ThCl₄), and plutonium trichloride (PuCl₃) serves as both the spallation target and the fuel. A 1 GeV proton accelerator with maximum beam current of 4 mA is introduced to compensate the neutrons absorbed by fission products during operation. By adopting an offline fuel cycle scenario based on the multi‐generation reactor evolution, the utilization efficiency of thorium fuel is greatly improved. After four generations of TMSFEA operation, the total net ²³³U production is 2774.6 kg, the fission rate fraction of ²³³U rises from 0% to 89.3%, the energy fraction of thorium (EFT) can achieve the value of 66.6%, and the utilization efficiency of thorium (UET) can reach 25.9%.