Abstract: Objective] The aim of the present study was to assess the toxic effects of environmental level triphenyltin （TPT） on mammalian adrenal gland. [Methods]Forty adolescent SD rats were randomly assigned to one of four groups：Three TPT treatment groups received intragastric administration with 0.5, 5, 50μg/ （kg·BW） of TPT every 3 days for 54 days respectively and one control group received no TPT. The mice were anesthetized with 10%chloral hydrate and killed. The paraffin sections of the rats adrenal gland tissues were prepared and stained by HE staining method to observe the variation characteristics of their structure. [Results]The tissue structure of adrenal gland of SD rats in the control group was normal; the structure of cells in zona glomerulosa, zona fasciculate and zona reticularis in adrenal cortex was normal, and the nucleus of the cells were limpid;the cells in adrenal medulla were polygonal or circular, the arrangement of the cells was irregular, and there was blood sinus among tissue space. Compared with the control group, there were no significant changes in the structure of the adrenal cortex and medulla in the low dose group. The zona glomerulosa of adrenal in the middle dose group was thinner than that in the lower dose group;there was the nucleus condensation and plasmolysis in the zona fasciculate and adrenal medulla cells, and there was slight bleeding in interstitial tissues. The number of zona glomerulosa cells in high dose group was significantly reduced, and the limit between zona glomerulosa and zona fasciculate was unsharp;the nucleus condensation and plasmolysis in cells in zona fasciculate and adrenal medulla was aggravated, and there was vacuolization in the cells;the interstitial tissues were thicken and bleeding was aggravated. [Conclusion]The results obtained in this study demonstrate that certain doses of TPT can cause damage to the tissue structure of adrenal gland in SD rats in a dose-dependent way. The results also provide morphological data for assessing the effect of TPT on mammalian endocrine function.