目的　建立白细胞及骨髓有核细胞减少的大鼠模型。方法　 2 0只正常SD大鼠 ,随机分成两组 ,试验组给大鼠腹腔反复注射环磷酰胺 ,对照组注射等体积的生理盐水。结果　试验组大鼠体重明显降低 ,白细胞及骨髓有核细胞数明显减少 ,且停药 15d时 ,白细胞总数仍维持在低值水平。结论　此方法建立的大鼠模型 ,低白细胞水平维持的时间长 ,能够满足实验研究需要的观察时间 ,可用于化疗毒性的治疗药物筛选及其他治疗手段的研究。 Objective To establish a rat model of leukocyte and bone marrow reduced nucleated cells. Methods Twenty normal SD rats were randomly divided into two groups. Rats in the experimental group were injected intraperitoneally with cyclophosphamide, while those in the control group were injected with equal volume of normal saline. Results The body weight of rats in test group was significantly decreased, the number of leukocytes and bone marrow nucleated cells was significantly reduced, and the total number of leukocytes remained at a low level after 15 days of withdrawal. Conclusion The rat model established by this method can maintain the leukocyte level for a long time and can meet the experimental observation time. It can be used to screen chemotherapeutic drugs and other therapeutic methods.