When heating and calcining the dehydrate gypsum and chemical gypsum (ardealite, desulphurization plaster, fluorgypsum), the dehydrate gypsum is decomposed, we get the semi-hydrated gypsum, i.e., plaster of Paris. According to the temperature and pressure during decomposition, the products include high intensity gypsum and plaster of Paris.The plaster breaking system, calcined system and grinding aging system are the main parts. The whole process is as following: Gypsum mine----- homogenization ---- rough breaking --- detailed breaking----Measurement(calculating)----calcined(oil,coal,dust-collector)--h omogenization(dust-collector)----grinding(dust-collector)---aging (dust-collector)----- package