SD rat is a common experiment animal in clinic iatrology, In this article, we studied the weight correlation among the main viscera of 24 SD rats. The result showed that there are no correlation (P> 0.05) between liver and heart, and they are also no correlation with other main viscera such as lung, spleen, kidney and stomach etc, while spleen has the distinct correlation with kidney (P < 0.01), stomach not only has the distinct correlation with lung and spleen (P < 0.01) it also has correlation with kidney (P < 0.05).