A method for observing patient abnormality during medical imaging, including: acquiring behavioral expression monitoring data of a patient during medical imaging; based on the behavioral expression monitoring data, judging whether human sound-making behavior is present and/or whether bodily movement behavior is present; and at least based on whether human sound-making behavior is present and/or whether bodily movement behavior is present, judging whether the patient exhibits abnormal behavior; and upon determining that the patient exhibits abnormal behavior, generating a signal to notify an abnormality observer. The method for observing patient abnormality allows the condition of a patient during medical imaging to be observed more conveniently. In addition, a system for observing patient abnormality is provided to realize the method for observing patient abnormality.