The present invention relates to a thermal treatment integrated fabrication system of a gas reactor nuclear fuel coated particle, and a manufacturing method of a nuclear fuel coated particle using the same. More specifically, the present invention provides a gas reactor nuclear fuel coated particle fabrication thermal treatment system comprising a supply gas preheating unit capable of recycling a waste heat of discharge gas. The gas reactor nuclear fuel coated particle fabrication thermal treatment system performs; a calcination process step of pyrolyzing a nuclear fuel fabrication intermediate material (ADU gel) and converting it into a sphere oxide particle; a sintering process step of revivifying and sintering the sphere oxide particle; and a coating process step of forming a plurality of coating layers on the sintered sphere uranium compound particle. In the thermal treatment integrated fabrication system of the gas reactor nuclear fuel coated particle according to the present invention, a heat treatment is executed within one device when the nuclear fuel such as UO_2 kernel or UCO particle is manufactured and the nuclear fuel particle is coated. Therefore, the present invention can reduce the effect of different heat treatment equipment unit processes and a traditional complex device which uses a heat treatment device for every manufacturing step. Also, pre-heating can be performed by collecting waste heat from waste gas through heat exchange, and the amounts of energy used to require pre-heating can be reduced.