Abstract: For the stability of the slope with goafs in Gongchangling open-pit iron mine，the influence of goafs with different size and position was considered. Numerical simulation was carried out by FLAC and Geo-slope software. Three conditions (including 36 cases) of the slope stability were simulated: ①without goaf；②goaf lies in the top, middle, lower part and bottom of the slope and the distance of all goafs from slope surface is fixed, and the width of the goaf is changed；③The size of goafs is fixed, and the distance from slope is changed. Through contrasting with plastic zone，displacement and safety factor of slope with different goafs, the influence law of the goaf on the slope stability was obtained. The results showed that the goaf in the upper slope is beneficial to the overall slope stability，but has influence on the local stability of the slope. The goaf in the middle slope has more complex influence on slope stability，both favorable or unfavorable for slope stability situation. The goaf in the lower part of the slope has serious influence on slope stability. This law has reference meaning in transferring from open-pit mining to underground mining.

Key words: Open-pit mine, Slope stability, Goaf, Numerical simulation, Safety factor