Abstract: Repeated blasting vibrations are one of important triggers of landslides, especially those developed on complex rock slopes with muddy intercalation. To reveal the failure mechanism of complex rock slope with muddy intercalation under repeated blasting vibrations, a novel method was proposed to evaluate cumulative sliding displacement and critical blasting times for this type of slopes based on the law of conservation of energy and Newmark sliding block method. In this method, the cumulative damage effects of repeated blast vibrations were characterized through multiple strength reduction factors of muddy intercalation parameters, e.g. shear modulus, dip angle and continuity. The importance of those parameters on slope cumulative sliding displacement was also addressed using sensitivity analysis. The proposed method generally shows more reasonable results regarding estimation of cumulative sliding displacement and critical blasting vibration times. The parameters of muddy intercalation show significant controls on the cumulative sliding displacement of slope under many times of blasting vibration. With the shear modulus increased, the cumulative displacement declines as the slope resistance gets enhanced. Steeper dip angle of muddy intercalation increases the slope displacement of creep section and has no obvious influence on the displacement of shear section. Higher continuity of muddy intercalation induces larger cumulative sliding displacement as expected. The sensitivity analysis results show that the cumulative sliding displacement under repeated blasting vibrations is influenced by shear modulus, followed by dip angle and continuity of muddy intercalation.