An object of the invention is to disclose a nested type reactor coolant pipeline for a nuclear power plant. The nested type reactor coolant pipeline includes a hot section and a cold section. The hotsection is composed of hot section straight sections and hot section bend pipes, and the cold section is composed of pressure vessel cold section connecting pipe seats and main pump cold section connecting pipe seats; the main pump cold section connecting pipe seats convey a coolant from a main pump outlet, and deliver the coolant to a reactor through the pressure vessel cold section connecting pipe seats; and the hot section straight section outputs the coolant to the hot section straight section through a hot section connecting pipe seat of a hanging basket, and then the coolant reaches steam generators through the hot section bend pipes. Compared with the prior art, the coolant of the reactor is transported to the steam generators through the hot section pipelines, and the coolant of the reactor is sent back to a reactor pressure vessel through the cold section pipelines to complete circulation, and therefore, an arrangement space is saved, a compact design is achieved, the occupation area of workshops is reduced, multiple loops can be copied, different power requirements are satisfied, and the object of the nested type reactor coolant pipeline is achieved.