The aim of this study was to investigate the effectiveness of customised safety interventions in improving the safety cultures of both clinical and non-clinical hospital staff. This was assessed using the Safety Attitude Questionnaire-Chinese at baseline, 2 years and 4 years after the implementation of safety interventions with a high response rate ranging from 80.5% to 87.2% and excellent internal consistency (Cronbach’s alpha=0.93). The baseline survey revealed a relatively low positive attitude response in the Safety Climate (SC) domain. Both SC and Working Conditions (WC) domains were shown to have increased positive attitude responses in the second survey, while only the Management Perception domain had gained 3.8% in the last survey. In addition, safety dimensions related to collaboration with doctors and service delays due to communication breakdown were significantly improved after customised intervention was applied. Safety dimensions related to safety training, reporting and safety awareness had a high positive response in the initial survey; however, the effect was difficult to sustain subsequently. Multilevel analysis further illustrated that non-clinical staff were shown to have a more positive attitude than clinical staff, while female staff had a higher positive attitude percentage in job satisfaction than male staff. The results showed some improvements in various safety domains and dimensions, but also revealed inconsistent changes in subsequent surveys. The change in positive safety culture over the years and its sustainability need to be further explored. It is suggested that hospital management should continuously monitor and evaluate their strategies while delivering multifaceted interventions to be more specifically focused and to motivate staff to be enthusiastic in sustaining patient safety culture.