The invention discloses a geological sedimentation monitoring device. The geological sedimentation monitoring device comprises two fixed ends, a fixed declinometer arranged between the two fixed ends in a distributed manner, and a connecting accessory, wherein a displacement meter is further arranged between the two fixed ends and on the geologic interface or the load abrupt change interface. The invention further discloses a geological sedimentation monitoring method applying the method. In the geological sedimentation monitoring device and the geological sedimentation monitoring method disclosed by the invention, the fixed declinometer and the displacement meter are combined to use to form the continuous distributed sedimentation monitoring device; the displacement meter is arranged on the geologic interface or the load abrupt change interface, so as to effectively prevent the abrupt increase/decrease phenomenon at an individual point due to abrupt change on the geological interface and the load and other factors, and facilitate the monitoring result to be more accurate, and closer to the fact.