Abstract: As one of the way of estimating microbial protein production, urinary purine derivatives (PD) is easier. And it has good consistency with any other ways, but it also has disadvantage. The PD excretion in urine changes and it is not universal in different breeds. So it is exactly in need of kinds of models about different ruminants. Three China Holstein male cattle were fed with three mixed diets of forage and concentrate. In this experiment, a Latin square design was used to research the rules of purine derivatives excretion through observing the relationship between DOMI and PD excretion. It shows that the allantoin, which only takes little part in calves, was the main part (about73%~88%) in the cattle’s urine, and the xanthine and hypoxanthine which are also take only much little part, can be neglected. The PD changed from 414.09mmol/d to 975.59mmol/d with the enhancement of DOM and DCP intake, and the relativity was significant (R2=0.88, n=9). At the same time, the creatine excretion was steady, and not significant (P＞0.05). The PDC increased with the enhancement of DOM and DCPI, which was consistent to other’s research of cattle and contrary to calves, but the response was lower.