In order to explore the road accident which brings about a threat against residents' life. We applied motorized extent of city (MEC, the rate per 1,000 persons possessing the number of vehicles), level of traffic safety (LTS, the mortality rate per 10,000 registered vehicles), level of personal safety (LPS, the mortality rate per 100,000 persons) to evaluate the relationship between secular trend of motorization and traffic mortality in China. Although increased by 100 times from 1949 to 1992, MEC was considered rather low in the whole country (MEC = 11.2%). When MEC was progressing while LPS was decreasing year after year, LTS has been improved since the late 1970s. The best records of MEC and LTS were noticed in Beijing and the best LPS was in Inner Mongolia. Throughout the 30 administrative areas, LPS has taken a favourable turn, while MEC and LTS abtained distinct improvement in certain areas. Thus one's personal safety is affected by both the synergism of motorization and the road safety level.