Based on the researches of evaluation methods about road traffic safety in China and abroad, the gray system theory is used for the first time in road traffic safety to set up a trigonometry whitening weight (TWW) function evaluation model in accordance with the request of China's present road traffic safety. And the evaluations of road traffic safety in 2003 in Shandong, Shanghai, Henan, Zhejiang，Guangdong and Jiangsu are studied and compared one another.