Abstract: In order to understand the influence of water on spontaneous combustion heating rate of coal pile, the 2D heat and mass transfer mathematical model of coal pile containing water was established. Then, Fluent software was used to analyze oxygen, water content and temperature in coal pile. The results show that coal pile containing water goes through three stages inclulding heating, slow heating and fast heating, and water in coal pile also has three matching stages inclulding slow evaporation, fast evaporation and drying. Then, the existence of water can slow down the coal pile temperature in middle-term of spontaneous combustion, and the higher the water content, the longer time needed for water evaporation, and the longer the safe storage time. The water content and safe storage time has a strong exponential relationship.