Abstract: The outer slope ratio of tailing dam is 1∶5 and the slope angle is 11° in dressing plant of Shunda Mining Company.When waste dumping covers the slope，the safety factor of tailing dam is increased to 1.915 from 1.628，and the saturation line is still maintained at a reasonable range.In order to guarantee the slope's drainage performance，it is significant that the vegetation in mine dumping range and the quaternary soft layer are cleaned up，and 2~3 m block stone are laid out on it.The research indicates that it is feasible to cover the outer slope with the waste dump in safety.It offers a reference to similar reinforcement projects of tailing dam.

Key words: Tailings dam, Waste dumping to cover slope, Safety factor against sliding, Saturation line