The new type of gypsum compound waterproof agent was composed of organic emulsion that emulsified by polyvinyl alcohol and stearic acid and saline waterproof agent made of carboxylic acid sodium, aluminium sulfate etc. The influences on the hydration exothermic effect and crystal growth of gypsum were studied when different amount of the organic emulsion, the saline waterproof agent were added. According to the hydration exothermic effect and microstructure of crystal growth of gypsum after mixing the different amount of waterproof agent, the relationship between gypsum hydration exothermic effect and gypsum crystal growth were discussed theoretically.