1. The target population and study sample The target population (i.e. clinical nurses) for the study is defined to be from a variety of ward such as Hematology, Oncology, Stroke and Rehabilitation where potential cases with high suicide risk may be identified. The investigators hypothesise that nurses who work in these wards should understand more about the concept of suicide prevention and suicide risk assessment. Therefore the study will include all clinical nurses in these wards as the target population. The sample size is calculated based on the suggestion in the literature, and the investigators set the significant level data, α = 0.05, power = 0.80. Then the investigators divide all study subjects into experimental group and control group randomly, and use different interventions to examine the effect of research.