The invention provides a geotechnical model test compaction device suitable for multiple working conditions. The geotechnical model test compaction device comprises a model box and the compaction device connected with the model box; the compaction device comprises a hydraulic device and a fixed device in sequential connection; a hydraulic rod is connected on the hydraulic device, the fixed deviceis a hollow structure, the hydraulic rod penetrates through the fixed device, and one end, penetrating through the fixed device, of the hydraulic rod is connected with a compaction steel plate; and asupport device is further hinged on the fixed device, and the support device is a handle-grasping type connecting device or an internal supporting connection device. The compaction device disclosed bythe invention is concise in design, comparatively flexible and convenient for operation, light in weight, and safe and reliable; the device has two operation modes, the compaction of the soil body atany location can be performed, and the device is detachable and free from occupying large use space.