The invention relates to a large-scale electric power inspection well body and a manufacturing method thereof. The inspection well body comprises an inner PVC plastic box, an outer PVC plastic box, a bar-mat reinforcement frame and concrete wholly poured into a cavity between the inner PVC plastic box and the outer PVC plastic box; and PVC plastic plates are cut and welded to form the inner PVC plastic box and the outer PVC plastic box, the bar-mat reinforcement frame is erected between the inner PVC plastic box and the outer PVC plastic box, and rapid set concrete is wholly poured in the cavity formed by the inner PVC plastic box and the outer PVC plastic box. According to the large-scale electric power inspection well body, plastic sheet segmentation module cutting and bar-mat reinforcement weaving can be carried out in a factory in a concentrated manner, and then the inner and outer plastic box welding and assembling and concrete overall pouring are carried out on site. According to the manufacturing method, the large or ultra-large type electric power inspection well bodies in different specifications can be produced, traffic transportation and on-site construction are facilitated, the electric power inspection well body is high in pressure resistance and anti-impact intensity, resistant to corrosion, good in sealing performance, long in service life and low in cost, and standardizing, universalization and serialization fast and efficient production can be carried out.