Majiagou group limestone in preheating and roasting process easily break into powder,seriously affect the normal production of lime,its quality cannot meet the needs of users.By comparative study of the properties of limestone in Majiagou group and Fengfeng group,the results show that the main reasons of limestone breaking in Majiagou formation include unstable aragonite phase,weak oxidation degree and a large number of closed pores and cracks in the structure,resulting in phase transition and volume expansion  of linestone in heating process.At the same time,the factors affecting the limestone breaking are analyzed,and the targeted measures are put forward.