The properties of the soil around buried pipelines vary in longitudinal direction, which directly affects the seismic performance and reliability of the pipelines. On the basis of design response spectra, artificial ground motions with different seismic intensities were generated, and a simplified elastic foundation beam model was adopted to analyze the dynamic response of pipeline joints under the seismic wave passage effect. Considering the reduction in the tensile strength of ductile iron water pipeline joints caused by factors such as installation difference and pipeline aging, the effects of four uncertain parameters (soil weight, internal friction angle, cohesion, and yield displacement of soil spring) on the seismic response of buried pipelines were investigated, and the uncertainties of soil parameters under different seismic intensities and weak joint ratios were analyzed. Results show that compared with the calculation results of the model with parameter certainties, and the influences of the four uncertain parameters on the peak dynamic response of joints from large to small were cohesion, internal friction angle, soil weight, and soil spring yield displacement. The model containing four uncertain parameters had the greatest influence on the results, and the variation coefficient of peak joint opening was up to 9.54%. The mean values of the conditions with parameter uncertainties were consistent with the results of certainty condition, and the most unfavorable values of uncertainty conditions were 1.1-1.3 of the results of certainty condition. Besides, the reduction in the tensile strength of the local joint had a significant effect on the response of the pipeline joint. On the basis of the numerical results, the prediction equations between the weak joint ratio and the peak joint opening under different seismic intensities were proposed.