A seal agent coating device is disclosed, comprising: a storage cavity, a nozzle, a connecting duct and a power driven component, wherein: the nozzle comprises a nozzle cavity and a mouth, the mouth being located at the lower part of the nozzle cavity and matching with the shape of the seal agent coating area of the substrate; the connecting duct interconnects the storage cavity and the nozzle cavity; the power driven component can squeeze the seal agent in the storage cavity into the nozzle cavity via the connecting duct, thereby squeezing it out via the mouth.