The invention discloses a reaction and separation integrated process and device for synthesizing poly-alpha-olefin (PAO). The reaction and separation integrated process comprises the following steps: putting an alpha-olefin raw material and a magnetic lewis acid catalyst in a ratio into a reaction and separation integrated device, after the reaction is completed, powering on an electromagnetic sucker inside a reaction kettle to magnetize the magnetic lewis acid catalyst to adsorb onto the surface of the electromagnetic sucker, and feeding a discharged reaction clean liquid into a next procedure. By adopting the reaction and separation integrated device, the problem that the lewis acid catalyst in PAO synthesis is hard to separate can be solved. By adopting the process and the device, PAO process procedures can be greatly simplified, the number of production devices can be reduced, energy consumption for separating the catalyst can be reduced, the production cost of PAO can be lowered, and green, environment-friendly and efficient production of PAO can be achieved.