Terahertz near-field scanning system uses high-power vacuum electron device as power output source, combined with nano-scale probe, has measurement accuracy of tens of nanometers imaging effect. Combined with the characteristics of terahertz penetration, the inner and surface of the sample can be imaged at the same time. In this paper, terahertz near-field scanning system is used to image human sperm in the field of biological samples. The shape, acrosome, nucleus and tail of human sperm are imaged on the surface or inside. The problems needing attention during the experiment are discussed. Finally, the significance of imaging experiment to biological research is prospected.