Light method and lighting device

The embodiments of the invention disclose a light method and a lighting device. A target illumination value of a target region is detected, and a power supply current value of a light emitting unit is adjusted according to the target illumination value, so that the target illumination value is enabled to be in a preset illumination range. No matter how is the light environment where the target region exists, the power supply current value confirming to the illumination range can be found, so that a good light environment is provided to people, and the eye health of the people is effectively protected.