Abstract: The change of allantion during cow dung and chicken manure composting was studied through the lab composting experiment (LCE) and outside compost experiment (OCE). The factors influencing the change of Allantion in the dung were analyzed. The effect of high concentration urea on synthesis and degradation of allantion was researched. The results showed that owing to difference of temperature and aeration conditions, the rates of decompost of cow dung differ in three different types of composting. The trend of allantion change during composting were parabola, and the rates of change were divergence. The highest value of allantion (0. 51%) of LCE was reached when the temperature declined to 49C, the highest value of allantion (0.38%) of the OCE(in jar) was resched in the 18th day when the temperature raised to 36 C. the highest value of allantion (0.43%) of OCE(on land) was reached in the 17th day when the temperature raised to 42C. The type of composting, kind of dung and rate of decompost affect allantion content. The faster manure decompostes and the higher dunghill temperature raises, the faster allantion content increses and the higher allantion content reaches during compost. The allanlion content of chicken manure was higher than that of cow dung throughout the composting. It is suggested that precursors content in the dung was decidedly factor affecting the allantion during composting. In anaerobic condition, the allantion content was remarkably increased by added 20% urea to cow dung. The allantion content in the dung treated with urea increased 42.2% in the 70th day, the allantion content in clung not treated with urea decreased more than 50%. This indicated that urea may be the allantion precursors and adding it to dung could induce allantion synthesis. As one of products of allantion degradation, urea could put off or control allantion degradation.