The purpose of this study is to analyze and explain the substance of psychiatric nurses` experiences in nursing care of client with delusion. This study utilized Grounded Theory method to find and understand the essentials of psychiatric nurses` experiences. The causal conditions of psychiatric nurses` experiences in nursing care of client with delusion shown in grounded data was `Pt`s delusion`, and the context was `course of delusion`. The central phenomenon was `unbearable`, and the interventional condition was `effort for trust`. In order to get out of the feeling of unbearable, psychiatric nurses use various strategies such as `reassuaring, giving empathy, letting go, encouraging expression of pt`s thought and feeling, focusing medication, assessing accurately, suggesting moving, giving reality`. Through theses strategies psychiatric nurses experienced following result: `recognizing the need for the details of nursing approach`. According to the nurses` strategies and results used to cope with the feeling `unbearable`, 3 types were found: self-reflector, negotiator, withdrawer. In conclusion, these results could enlighten the challengeable phenomena which made psychiatric nurses feel helplessness and self-doubt in nursing care for pt`s delusion. Much more attention for nurses` feeling and response in order to give the most comprehensive nursing care will be suggested.