Based on the portal landscape design scheme of Ban-lun Tunnel in Yunnan Province, we selected four primary influencing factors including portal linetype, portal color, portal greening, and portal texture. An orthogonal experimental design was adopted, and nine model schemes were established. A driving simulation test was conducted using a driving simulation test system and eye tracker, meanwhile, the pupil diameter and the sight deviation time were selected as evaluation indexes. The results show that in terms of portal landscape driving comfort, the order of importance of the four factors is as follows： portal texture, portal greening, portal color, and portal linetype. The distractions of drivers appear in the fifth model （green end wall, mural, city wall type, and natural greening）, and the ninth model （grey end wall, mural, arc line type, elaborate greening）, leading to the potential safety hazard of driving. Based on the experimental results, some optimization suggestions were put forward for the tunnel portal landscape design from the aesthetic aspect.