[Objective] A suitable quality evaluation system for ecological slope protection was established to evaluate the quality grade of ecological slope protection project, and to provide a theoretical basis for selecting the slope ecological restoration method.[Methods] In combination with the system engineering theory, the ecological slope protection engineering is regarded as a complex system of "slope-matrix-plant community". A new evaluation model of unascertainty measure and set pair analysis were established to be used in the process of ecological slope protection project quality evaluation. Using unascertained measure theory, the multi-index comprehensive measure evaluation vector of each ecological slope protection scheme was calculated, and the uncertainty information in the ecological slope protection system was transformed into relatively unascertained information. The pair analysis reflects the degree of similarity, difference and inverse relation between the certainty and uncertainty of ecological slope protection system, and further improve the accuracy of evaluation. Finally, the model was applied to evaluate three alternative schemes of railway slope ecological restoration project.[Results] The quality standard of the three kinds of schemes are all level Ⅱ. The correlation numbers index were:0.384, 0.386 and 0.539, respectively. The results showed the third option (TBS Ⅱ slope protection) was the best.[Conclusion] The result of optimization was almost consistent with the calculation result of grey evaluation model and reflected the result of engineering practice well. We concluded that the method adopted in this paper is an effective new method to study the effect of ecological slope protection.