The invention discloses a nuclear island cavern group annular arrangement underground nuclear power plant comprising a nuclear island producing steam with nuclear fission energy. The island is arranged in an underground cavern group. The underground cavern group comprises a reactor factory building cavern used for accommodating a reactor factory building and an auxiliary factory building cavern group, all of which are arranged underground. The auxiliary factory building cavern group is annularly arranged around the reactor factory building cavern. With the underground nuclear power plant nuclear island cavern annular arrangement form, existing underground cavern evacuation technologies can satisfy the construction requirements of the underground nuclear power plant. Being annularly arranged, the cavern group has an arrangement position substantially same with that of nuclear island factory buildings of a ground nuclear power plant. Therefore, less adjustment is required on an existing ground nuclear power plant technology system.