Abstract: In order to reflect situation that whether products meet index requirements in coal preparation plant, a multi-level fuzzy comprehensive evaluation method was proposed. Taking production data of seven months in one coal preparation plant as research object， the heavy medium separation product index, the coarse slime separation product index and flotation product index were concentrated to form a fuzzy relation matrix, the weight vector was constructed by expert scoring method. And the production data of seven months was calculated by the multi-level fuzzy comprehensive evaluation method. The evaluation results indicated that the optimal target was January and July, and separation effect of February to May was suboptimal. By contrast, separation effect of June was unfavorable. This conclusion is in conformity with field separation effect.