A luminous intensity test device includes an optical frequency converter, a display, and a processor. The optical frequency converter selectively converts at least a portion of light emitted by a light source into a digital signal. The display displays a color selection interface. The processor processes the digital signal and obtains the luminous intensity. When a tester inputs a color parameter into the color selection interface via an input device, the optical frequency converter converts a kind of light to the digital signal and then the processor processes the digital signal to obtain a luminous intensity and display the luminous intensity on the display.