Objective To study whether the growth of rats will be improved by recombinant human lactoferrin (rhLF) separated and purified from transgenic cow milk. Method rhLF was administered by gavage to 4 groups of 14 male weaned Wistar rats at doses of 0.375, 0.75 or 2.25 g/（kg bw?d） for 56 days. Body weight, body length and food consumption were recorded at regular intervals. Results Compared with the control group, the physical parameters including body weight, body length and food utilization were improved obviously in the high dose group. There is a slight improvement on physical parameters in the low and medium dose groups. Conclusion Recombinant human lactoferrin might show a function of improving the growth of rats in this study.