Purpose: Objective of this study was to investigate how often nurses to perform patient safety activities. Methods: 521 observations were collected in 9 hospitals by 107 nursing students. Nurses' patient safety care activities were measured 0 (not at all) to 10 (all the time) scores. Descriptive statistics, independent t-test, one way ANOVA, correlation, multiple regression used to analyse data. Results: Items like 'Initial nursing assessment', 'drug management bring on', 'preparation for radiology test', 'falls assessment', 'nursing record' got high scores. But, scores of 'patient identification', 'verbal order management', 'hand hygiene' were lower than others. Each scores were different significantly according to institutions and departments. Within a same institution, the variance of scores, especially in 'patient identification', 'hand hygiene' were great. Scores of activities were different according to characteristics of institutions like type, location, number of beds, teaching hospital, number of accreditation, JCI accreditation. Predictors influencing nurses' patient safety activities were type, location and accreditation. These predictors account for 19.4% of variance. Conclusion: Performance of nurses' patient safety activities were different significantly according to characteristics of institutions. The important items like 'patient identification', 'hand hygiene' had achieved lowest performance. Further researches are needed to improve the basic safety activities.