Seismic indexes of bedding rock slopes are mostly uncertain and cannot be measured by a fixed threshold. An uncertain analysis-based method of measuring the seismic behavior of bedding rock slopes is proposed. The bedding rock slope is regarded as several superimposed thin plates. The dynamic safety factor and the dynamic limit state equation of each thin plate are calculated by an uncertain analysis method, and the dynamic limit of bedding rock slope is calculated. The relationship between the dynamic reliability index and failure probability of the bedding slope under earthquake can be obtained by solving the dynamic limit state equation, and the overall stability of the bedding slope can be evaluated under seismic force. The minimum average safety factor and average failure probability of the bedding slope can be comprehensively considered, and the evaluation results can be obtained. The experimental results show that the height, angle, and dip angle of the bedding slope have a significant influence on the seismic performance of the bedding slope under seismic force, and the evaluation results are consistent with the actual results.