This study intends to identify critical demographic variables that would significant influence on each dimension of the patient safety culture. The internal survey data sets in 2015 and 2016 from the entire medical staffs’ viewpoints are used. Linear regression with forward selection is applied where ten demographic variables are the input variables, while each dimension of the Chinese version of the safety attitudes questionnaire is the dependent variable. Supervisor/manager is the most essential demographic variable that has significant impacts on six dimensions. Experience in position is the other critical demographic variable. Therefore, hospital management needs to focus on medical staffs who are not supervisors/managers first in order to improve the patient safety culture in this regional teaching hospital.