We investigated a methodology to design light-triggered thyristors thanks to TCAD. The simulation model accuracy, especially the holding current and the minimum incident light intensity to turn-ON, were compared with experimental results. The influence of SiC epitaxial layer lifetime and the incident light properties (wavelength and intensity) on the optically triggered 4H-SiC thyristor characteristics have been studied by simulation. We considered the wavelength dependence of quantum efficiency, penetration depth, and photon energy. The holding current and turn-ON time depends on the lifetime. The minimum intensity to turn-ON the device significantly depends on the wavelength. This intensity becomes less than 0.003 times when the wavelength changed from 380 to 325 nm. In addition, the breakover voltage is affected by the constant incident light even if the intensity is tiny.