Abstract: In order to study the drivers' vehicle speed control mode on the sections with combination of vertical and horizontal curve of mountainous freeway, a preview-based drivers' fuzzy input and output parameters set was established on the sections with combination of vertical and horizontal curve. A vehicle speed model with 101 fuzzy control rules set was set up by field tests, and a measured test was implemented on 6 typical sections of Xi'an-Hanzhong freeway to verify the model. The results showed that the predicting results were highly consistent with the measured test results and the rightness of the model, the relative error of accuracy was 3.8%.