Objective To investigate the protect effect of tetramethylpyrazine on the kidney of the small intestinal transplanted rat which having been cured by CsA.Methods Rats are divided into two groups.Group I: Wistar→SD Small intestinal transplantation +CsA.Group Ⅱ: Wistar→SD Small intestinal transplantation +CsA+ tetramethylpyrazine.We investigated the pathologic changes of kidney at 14th day after operation and detect the BUN and Cr in the blood serum.Results Group I had obvious pathologic change,Group Ⅱ changed little.The BUN and Cr in Group I raised higher than in Group Ⅱ.It had statistic significances between the two groups(p0.01).Conclusion Tetramethylpyrazine can protect the kidney of the small intestinal transplanted rat which having been cured by CsA