An exemplary wet coating system includes a coating chamber, an annealing chamber, an unloading chamber, and a mechanical arm. The coating chamber is configured for allowing a substrate being wet coated therein. The unloading chamber is configured for allowing the substrate being unloaded therein. The annealing chamber is interposed between and communicated with the coating chamber and the unloading chamber and is configured for allowing the substrate being annealed therein. The communicated coating chamber, annealing chamber, and unloading chamber are vacuumized. The mechanical arm is configured for holding the substrate and moving the substrate across the coating chamber, the annealing chamber, and the unloading chamber.