China has the largest number of two-wheelers and relevant accidents in the world. The two-wheeler riders have a high level of vulnerability, creating a significant necessary to better understand the characteristics specific to this road-user group. The objective of this paper is to research the characteristics and causes of two-wheeler accidents in China by the use of CIDAS ( China In-Depth Accident Study) Database. 2012 cases of two-wheeler accidents with cyclists injured or dead were collected from CIDAS Database during 5 China cities (Changchun, Beijing, Weihai, Ningbo, and Foshan) over a period of 5 years (2011.06–2016.06). Several parameters such as accident type, region distribution, weather condition, environment and accident scenarios are analyzed using the data. The result shows that time-series data on road accidents involving two-wheeler riders are correlated with basic safety parameters, such as road type, season of the year, age and gender. The two-wheeler drivers’ injury information was also queried from CIDAS Database for a detailed study regarding injuries and their sources. The results of the analysis allow for an overall assessment of the two-wheeler riders safety level in China, thus providing a useful support to decision makers working to improve the protection of two-wheeler drivers from fatal accidents by a series of countermeasures.