Abstract: In order to make the driver enter the tunnel in a safe and comfortable state at night, when the driver entered bright environment from the dark environment. And the relationship was analyzed between the changes in environment from the darkness to brightness and traffic safety, a theoretical and experimental study was done for the lighting demand. A regression model of visual cognition distance and luminance difference was established with the target recognition test at different vehicle speeds. Finally, the luminance difference threshold was got for night tunnel entrance section at different vehicle speeds. The conclusions can provide a reference for the understanding and solving night entrance security issues and energy saving issues.