Objective To study detecting method of t etramine in biological samples. Methods Gas Chromatography/ Mass Spectrometry with selecti ng ion monitoring (SIM). Results The average recovery of tetramine in biological samples was 73.5% and RSD was 0.75%( n =6). Conclusion The method was quick and exa ct.I ts results can be used to provide evidence for clinical diagnosis and investigat ion of criminal cases.