The invention discloses a production device and a production process of p-xylene. The device comprises a xylene fractionation unit, an adsorption separation unit and an isomerization reaction unit, wherein the adsorption separation unit comprises an adsorption separation tower, an extraction liquid tower, a raffinate tower, a finished product tower, a finished product tower reboiler I and a finished product tower reboiler II, and the isomerization reaction unit comprises an isomerization reactor, an isomerization product fractionating tower, a white clay tower, an isomerization reaction heating furnace, a heat exchanger II, a heat exchanger III, a heat exchanger IV, a heat exchanger VI and a compressor. According to the process, the operation load of the xylene tower is reduced, the fuel gas consumption of the xylene reboiler is reduced, meanwhile, the heat exchange network is optimized, the fuel gas consumption of the isomerization reaction heating furnace is reduced, the energy consumption is greatly reduced, and the economic benefit and the social benefit are improved.