By studying the phenomenon that calorific value increases with the particle size reduction of coal Gangue by crushing in different ways, the paper analyzes the relationship between particle size and calorific－value distribution of crushed coal gangue. The results show that calorific－value of different size fractions redistribute with granularity changes, presented negative correlation; while the calorific value of fine－grained level increases by more than 1 times than coarse fraction, the results could provide the technological base of crushing and separation of coal gangue.