The attenuation law of ground vibration of viaduct rail transit under sloping bedrock condition is studied by model test and finite element method. The effects of inclination angle, load frequency, pile length on ground vibration were analyzed. The results indicated that under the condition of inclined bedrock, the attenuation of ground vibration is different in directions. Generally, the attenuation is the slowest along the downward slope of bedrock, while the fastest along the upward slope. The attenuation is gradually faster from the downward to the upward; The greater the inclination angle of bedrock layer, the lower the ground vibration response. The change of bedrock angle has a significant influence on the directional differentiation of ground vibration response. With increase of load frequency, the vibration response of the ground increases linearly first then decreases gradually. When the frequency is 13 Hz, the differentiation of vibration response on the ground is the greatest in all directions at the same distance to the pile. The surface velocity response decreases linearly with the increase of pile length. The nearer the pile, the faster the decrease. The influence of the change of pile length on the vibration response in all directions with the same distance to the pile is insignificant.