We used importance-agreement analysis to identify critical factors of the hospital survey on patient safety culture from the perceptions of physicians and nurses of a regional teaching hospital in terms of major strengths, minor strengths, minor weaknesses, and major weaknesses. In addition, we collected the raw data from 2011 to 2013 such that the advantages and deficiencies can be traced on a timely basis to enhance patient safety culture. The results show that there are 22, 21, and 21 items belonging to major strengths in 2011, 2012, and 2013, respectively. In contrast, there are 4, 5, and 5 items classified into major weaknesses in 2011, 2012, and 2013, respectively. This study also summarized the similarities and differences in this three-year period. Twenty items are the major strengths. On the contrary, only three items belonged to major weaknesses. Another viewpoint was also provided by taking into account genders in this three-year period. In summary, the hospital management can organize strategic adaptations to improve patient safety by observing the trends of strengths and weaknesses, as well as the similarities and differences in this three-year period. Therefore, hospital management can take appropriate actions to maintain the advantages and address deficiencies in order to enhance patient safety culture in this case hospital.