Abstract: Objective 　To study the bladder int ravesical instillation methods in pure line LEW rat and nude mouse. Methods 　Female LEW rats and nude mice were dissected and the urethra and bladder were observed though anatomic microscopy . The ink was poured into the bladder though urethra of female rats and mice with a t rochar. Filling and staining of bladder were observed and evaluated though the anatomic microscopy. Status and urethral injury of rats and mice were observed. Results 　Obvious urethra anatomic different were discovered between rat and human. The success rate of intubation tube is high (100 %) . States of animals weren't influenced by int ravesical instillation. Conclusion 　Bladder irrigation may be a kind of valid and utilized methods in pure line rat and nude mouse . The model may be a more effective tool for studying of bladder tumor.