Abstract: In order to evaluate the discomfort glare of the light spot which is caused by the tunnel sunshade, the glare influence of the projected sunshade light spot is analyzed, a quantitative method for evaluating the glare comfort of tunnel sunshades is established, the UGR of the projected light spot of sunshades with equal grilling distance is calculated, the relationship among light spot width, luminance and UGR are analyzed using UGR which is to evaluate the glare degree in lighting places. The results show that at the tunnel access zone, the smaller the luminance,the width of the bright area of the sunshade light spot and the UGR, the better the comfort, and vice versa; if the luminance and the width are more than a certain value and UGR is larger than 22, the discomfort glare is large and it affects the driving comfort. Finally a proposal for the design of sunshades is proposed.