The study aimed to investigate the situation of road accidents and then the risk factors of severity of road accident injury incidence in Kut Bak District, Sakon Nakhon Province. This retrospective research was studied from 2019 to 2021, Kut Bak Hospital treated 1,113 cases of people injured in traffic accidents. Data were collected from road accident records. All data were analyzed by descriptive statistics, and the risk factors of severity of road accident injury incidence were analyzed by Odd Ratio, 95% Confidence Interval of Odds Ratio.The study results showed that 1,113 people had an accident of males 66.2%, age group between 15 to 24 of 31.9%. The time period of the accident was 4 - 6 p.m. for 18.1%, motorcycle drivers of 85.5%, and without parties for 52.20%. They were not wearing safety helmets of 93.3%, not safety belts of 62.8%, and on the country road of 51.9%. The mind severity level of road accidents of 78.7%, and the high level of 21.3%. Furthermore, the death rate was 19.06 per 100,000 population. The comparison of the severity of road accident injury incidence was lower than the standard of Thailand (22 per 100,000 population (p<0.05). And then, the risk factors affecting the severity of road accident injury incidence were personal factors, physical, environmental, and protective factors (p<0.05). Most of injuries from road traffic accidents are mind severity level. The main reasons of them are personal factors, physical factors, and legal factors, which affect to severity of accident victims.