Objective To study the anatomic feature and the function of kidney in Smad3 gene knock-out mice. Methods The blood parameters of kidney drainage were measured by anatomical method and by VITALAB. Results There were significant difference in mice between types and age of Smad3 gene knock-out mice the homozygous mutants . The parameters of Cre,avoirdupois, kidneys and adrenal gland were significant differences between three types in 35 days mice :the parameters of the UA and BUN were higer than those of heterozygous mutants ,and the parameters of avoirdupois and visceral coefficient were lower than those of wildtypes ,but the parameters of Cre and BUN were higher than wildtypes. The parameters of UA of 70 days homozygous mutants were higher than wildtypes, but UA of 6 months lower. There were no significant differences in homozygous mice ,but parameters of Tbili ,Cre and BUN were higher in 6 months, the UA was higher in 70 days. Conclusion The metabolite outcomes were different in different ages of the mice . There were 12.5% one-kidney-mice which were produced by homozygous mutants,but the adrenal glands in existence. It was showed that Smad3 gene konck-out affected the formation of the kidneys.