An ultraviolet curing device and a control method thereof. The device comprises an ultraviolet light source and a controller connected by means of a cable. The ultraviolet light source is a water-cooled ultraviolet light source or an air-cooled ultraviolet light source. The controller is provided inside or outside of the ultraviolet light source. The ultraviolet light source comprises a shell (101), a copper substrate (103), multiple paths of LED chips (104), and a cooling assembly. The controller comprises a constant-current circuit board (105). The constant-current circuit board (105) performs multi-path constant -current control on the multiple paths of LED chips (104) to monitor anomaly of the voltage drop of the multiple paths of LED chip (104)s, thereby achieving control of the multiple paths of LED chips (104).