Abstract: Objective The effects of transport stress on liver,gill and spleen tissue structure of juvenile Eleutheronema tetradactylum were studied in order to improve survival rate of it and provide technical support for mass production of this species.Method As the research object,juvenile E.tetradactylum were divided into control group (no transport),mixed group(transport,while adding anti stress mixture) and blank group(transport,adding no anti stress agent).The anti stress agent was vitaminC ∶ glutamine =1 ∶ 1.Mixed group and blank group juvenile were sampled (liver,gill and spleen) 6 h after transport,cell morphology,tissue structure,life and physiological state were observed by paraffin section and HE staining under microscope.ResultThe results showed that normal performance and no death was found in the control group,mortality rate was 12.5% in mixed group,and the cumulative death in the blank group was 27.5%.Normal morphology was observed referring to the tissues in the control group.Cells arranged loosely in part of the of juvenile liver,and liver plate structure was not clear in mixed group.The liver tissue lost its intrinsic shape as a whole,liver plate structure disappeared and most nucleus were denaturation in oval or fusiform shape.The gill filaments were arranged irregularly,and a few or the whole of gill fragments swelling,red blood cells accumulated in part of the sinus,and mitochondria rich cells became larger in mixed group.Gill lamella swelled generally,the blood sinus broadened,part of the gill lamellae was busted because of too many red blood cells inside,and the mitochondria rich cells became larger and the number increased in blank transport group.The areas of white pulp of spleen increased and the number and size of melanin-macrophage centers increased in mixed group.The red pulp took up a majority area of spleen tissue,while the white pulp area was relatively smaller and distributed scatteredly,and the melano-macrophage centers (MMCs) was reduced in blank transport group.Conclusion The results of this study indicate that transport stress results in liver,gill and spleen tissue damage in juvenile E.tetradactylum.Although a mixture of anti stress drugs can act as a relief to some extent,the damage can not be completely eliminated.