The invention belongs to the technical field of group pile nuclear power plant arrangement, and specifically relates to a linearly-arranged modular reactor thermal power plant group pile. A plurality of modular reactors are linearly arranged in one reactor plant, and share the reactor plant, an electrical plant, a nuclear auxiliary plant and fuel storage and transfer facility. The plurality of modular reactors share a fuel transfer channel, and each two modular reactors jointly drive one steam turbine generator unit to generate power. The modular reactors are arranged in a steel safe case, and the internal diameter of the steel safe case is 18m. The upper half part of the steel safe case is immersed into a shielded pool, and the capacity of the shielded pool is 3000m<3>. The shielded pool has functions of biological shielding, the hot trap of safe case cooling, the hot trap of reactor emergent waste heat discharge and a function of providing reactor refuelling water. The group pile can solve a problem of economical performances of a small-size reactor thermal power plant in a better way.