Abstract: In order to study the relations of Eimeria perforans and Cyniclomyces guttulatus to diarrhea of rabbit. C. guttulatus and E. perforans isolated by our research team were used to infect experimental rabbits， respectively. Between 4 to 6 days after the inoculation with E. perforans， drinking， food intake and feaces excretion were obviously decreased in the inoculated rabbits. And diarrhea and death were found between 12 to 14 days after the inoculation in the third group， the diarrhea and death rate were 50% and 25%， respectively. After the inoculation with C. guttulatus， neither diarrhea nor death was found. Thus， E. perforans is pathogenic and one of important pathogenies to the diarrhea of rabbit， and C. guttulatus is non\|pathogenic to the diarrhea of rabbit.

Key words: Eimeria perforans, Cyniclomyces guttulatus, diarrhea, rabbit