The invention discloses a phosphate fire-resistant oil regeneration treatment device and method. The device comprises an oil inlet pipe and an oil outlet pipe which are connected with an oil outlet end and an oil return end of a thermal generator set, an oil inlet valve and an oil outlet valve are arranged on the oil inlet pipe and the oil outlet pipe, an oil quality index detection unit and a heater are arranged on the oil inlet pipe, regeneration branch pipes are arranged on the oil inlet pipe, regeneration filters are arranged on the regeneration branch pipes, a primary filter is arranged on the oil inlet pipe, an oil inlet branch pipe is arranged between the oil inlet pipe and the oil outlet pipe and positioned between the heater and the primary filter, a fine filter is arranged between the oil inlet branch pipe and the oil outlet valve, oil circuit switching valves are arranged on the oil inlet branch pipe, the regeneration branch pipes and the oil inlet pipe between the regeneration branch pipes, and the oil quality index detection unit and the oil circuit switching valves are connected with a control unit. The method includes the steps: S1 detection heating; S2 oil circuit switching treatment; S3 keeping of step S1 and S2 cycle. The device has the advantages of low cost, energy conservation, environmental protection and capability of improving fire-resistant oil regeneration effect and regeneration efficiency.