The invention discloses a displacement experiment device which comprises a displacement fluid supply system, a crude oil supply system, a displacement system and a monitoring system. The displacementsystem comprises a rock core model and a clamp holder, the rock core model is fixed into the clamp holder, an injection pipeline is connected with an inlet end of the clamp holder, an output pipelineis connected with an outlet end of the clamp holder, two back-pressure valves arranged on the injection pipeline and the output pipeline, and a pressure measuring device is arranged on the injection pipeline or the output pipeline; the displacement fluid supply system and the crude oil supply system are communicated with the injection pipeline; the monitoring system is set in such a manner that displacement procedures inside the rock core model can be monitored by the monitoring system. The displacement experiment device in an embodiment of the invention has the advantages that displacement fluid and crude oil displacement procedures can be simulated by the displacement experiment device, and the pressures of the back-pressure valves can be adjusted, so that displacement procedures under different experiment pressures can be simulated.