China In-Depth Accident Study (CIDAS) group collects accident data by on-scene investigate way in Changchun, Beijing, Weihai, Ningbo and Foshan. Based on the CIDAS data, this study analyzed the group characteristics and body injury distributions of the casualties in motorcycles, electric bicycles and bicycles. As a result, the mixed driving is the major environmental factor for cars to two-wheelers accidents, and most of such accidents happened in crossroads. Moreover, 16 to 65 years old two-wheelers injury users accounted for 62.0% of the total two-wheelers casualties.Within the two-wheelers injury users over 46 years old, users with AIS4 injuries occupied 22.4%. Besides, AIS4 bicycle injuries over 46 years old accounted for 47.6% of the total injury users over 46 years old. A similar injury parts distribution and AIS grade distribution in the same injury part were found among the casualties of motorcycles, electric bicycles and bicycles users.