Objective: To explore the establishment of non-renal injury model of urinary stone. Method: One hurdred SPF male SD rats were divided randomly into five groups.We administrated the animals chemical pure melamine 0.4-0.7 g ·kg-1 ·d-1continuously 20 d and 30 d

then observed and compared the rate of stone formation and renal damage. Result: Administration of chemical pure melamine 0.4

0.5 g ·kg-1 ·d-1

20

30 d

gained the highest rate of bladder stones formation

respectively

60% and 50% in 20 d

50% and 60% in 30 d.The difference of rate of bladder stones formation between group 0.4 g ·kg-1 ·d-1 and 0.5 g ·kg-1 ·d-1

and between group 0.4

0.5 and 0.6

0.7 g ·kg-1 ·d-1

blank control group were significant(P<0.05).Rate of bladder stone formation was not correrated with the increase in dose and time.The group 0.4 g ·kg-1 ·d-1is the only group that has no significant difference in the compare of renal and bladder index

creatinine

urea nitrogen

uric acid with the control group. Conclusion: Administration of chemical pure melamine 0.4 g ·kg-1 ·d-1 did not cause kidneys injury and was able to induce high rate of SD rat bladder stone formation(60%).So this method is suitable for the establishment a non-renal injury model of urinary stones.