Abstract: Compared with mercury-vapor lamp, ultraviolet (UV) LED suffers from the disadvantage of having a single wavelength, which is not fully compatible with the existing photoinitiator of ultraviolet ink. It is difficult using UVLEDs to achieve the curing effect comparable to what mercury-vapor lamp can do. This article presents a design of UVLED ink curing system that provides evenly mixed light with multiple wavelengths. We put a UVLED array with three wavelengths on a cambered surface and achieved uniform illumination in ink curing area by using optical freeform surface. By adding the adjusting of the tilt angle, we solved the dilemma of uniform wavelength mixing and uniform illumination. The ray tracing simulation results show that an illumination spot with uniform wavelength mixing, an average illumination of 110.7 mW/cm², and an illuminance uniformity of 0.82 is obtained on a target surface 600 mm away from the light source. This design is expected to simulate the multi-spectral illumination effect of mercury-vapor lamps, which can promote the application of UVLEDs in ink curing.