In intense and fast road cycling races, various accidents pose a great threat to cyclist safety. There is a lack of in-depth research on helmet performance and cyclist head injury in road cycling races. In this paper, based on collecting and summarizing the typical accident scenarios of road cycling races, models of road bicycle, anthropologic characteristics of cyclists and helmets are constructed with experimental and computational methods, and the head injury protection performance of helmets and cyclist's head injury response in typical accident scenarios are comprehensively analyzed and evaluated. The results show that the helmet can play a significant injury protection effect, but serious head injury may still occur in some scenarios; different helmets have significant differences in cyclist's head injury protection, and there is no direct correlation with the price. There are significant differences in the effectiveness of helmets for head injury protection among cyclists of different body sizes, with the 50th percentile adult men having the lowest peak kinematic response and injury risk, the 5th percentile adult women having the highest predicted values for all injury criteria, and at least 55% of female cyclists having a significant risk of skull fracture and severe brain injury. None of the accident boundary parameters examined in this study (accident speed, friction coefficient, and slope) had a significant effect on cyclist head injury in the accident scenarios; the Union cycliste Internationale stipulates that helmets may not be worn five kilometers from the end of the climb, while this study recommends cyclists wear safety helmets throughout the road cycling races. This study will provide a reference for the design of safety helmets for road cycling races, as well as data to support the improvement of road cycling race rules.