Posttraumatic stress disorder (PTSD) is an anxiety-related disorder that occurs after an exposure to an emotionally traumatic event, such as a life-threatening experience, and that persists with intrusive and distressing emotion-laden memories. It can trigger further mental health problems, such as depression, bipolar disorder, mania and so on. As a large population suffers from these complex diseases, its treatment results in massive secondary costs to society. Recent diagnosis and treatment of PTSD is based on relatively subjective assessments through diverse symptoms checklists, clinical histories, mental status exams, patient self-reports, and symptom duration. Biological markers have not been identified, and a biochip for PTSD has not yet been developed. In this paper, we briefly review potential biomarkers that could be used to determine the disease stage of PTSD, and we propose new applications of biochip technology with which PTSD could be precisely measured in real time using body fluids, such as blood, saliva, and urine. Microfabrication techniques have made it possible to construct nano/micron-scale sensing parts/chips to accommodate molecular linkers and capture the biomarkers for PTSD. These techniques provide new opportunities to diagnose PTSD in a precise manner.