Multiple numerical models were established by Computational Fluid Dynamics (CFD) method, and the reliability of the numerical results was also verified by the comparison with that of a wind tunnel test. The CFD analysis was then systematically carried out to study the influence of three geomorphological factors, the length of the canyon, distance between two peaks, and slope of the mountain, on the mean wind speed-up effect. The analysis results showed that the speed-up effect at the mountaintop was significantly affected by the slope of the mountain. The larger the slope was, the more significant the speed-up effect was in the near surface. Furthermore, the speed-up effect inside the canyon was influenced by the multiple geomorphological factors, and the variation trends were complicated. Therefore, the influence of the side slope boundary layer of the canyon and the three-dimensional effect of airflow should be considered. When the length of the canyon and the distance between two peaks decreased, and the slope of the mountain increased, the speed-up effect at the windward canyon entrance was more obvious in the near surface. Finally, the wind pressure terrain correction coefficient of the typical canyon was calculated and compared with the prescription of Chinese design code for building structures.