Professor, Chief Forensic Physician, Doctor student advisor, Chair of Department of Forensic Science, the principal teacher of the first batch first-class course of national-level virtual simulation experiment, the Young Backbone Teacher of Hunan Province. Prof. Guo mainly engaged in the scientific research field of postmortem interval estimation and complex cause of death analysis. As the principal investigator, Prof. Guo undertook three projects of National Natural Science Foundation of China and two projects of Hunan Province Natural Science Foundation, published more than 30 academic papers. He is the member of youth editorial board of “Forensic Science Research” journal, and the review expert of “Forensic Medicine” journal. He directly supervised or conducted more than 1000 autopsy cases as well as more than 200 cases of death-related medical disputes, and participated in a number of death cases with significant social impacts. Prof. Guo serves as the steering committee member of the Forensic Medicine Association of China, the deputy secretary-general of Hunan Judicial Authentication Association, the executive steering committee member of Hunan Entomology Society, visiting graduate student advisor of Xinjiang Medical University, the member of Beijing Municipal Public Security Bureau's expert board of forensic clinical and complicate cases, training instructor of Henan Public Security Judicial Authentication Center, distinguished visiting instructor of Physical Evidence Laboratory at Changsha Public Security Bureau, and the judicial appraisal expert of Hunan Medical Association.