Abstract: In order to study the difference of spontaneous combustion tendency among different coal piles in open-pit coal piles, numerical simulation method was used to analyze the overall temperature and CO distribution of coal piles under three arrangement modes: low first and then high, equal height, high first and then low. The results show that the shape and scale of the first coal pile facing the wind will affect the air leakage intensity of the rear coal pile, the higher the first coal pile, the less easy it is for the wind to pass directly into the second one; when stacking for 18 days, the area of high temperature zone in the coal piles with the arrangement of high first and then low is significantly reduced compared with the other two arrangement modes; CO is most likely to gather in the area between two coal piles, and the uneven height of the coal piles is easy to cause the wind to bypass the coal piles and form a large area of low-speed eddy, generating the CO rich area; when the coal pile spacing increases from 2 m to 8 m, the CO mass fraction between the coal piles decreases from 2.3×10^-5 to less than 1.2×10^-5, each coal pile in the coal piles presents a different risk of spontaneous combustion. In daily safety management, the spontaneous combustion characteristic of each coal pile should be considered, the fire prevention technical plan should be made reasonably, and the fire prevention measures should be taken in time.