The invention discloses a device for testing self-repairing of oil well cement. The device comprises a slurry cup for holding a to-be-tested cement rock; a heating unit for heating the to-be-tested cement rock in the slurry cup to a pre-set temperature; a pressure liquid-supply unit for injecting a liquid at a pre-set pressure into the slurry cup; and a monitoring unit for collecting a flow parameter of the fluid in real time. The invention further discloses a method for testing self-repairing of cement through adoption of the device for testing self-repairing of oil well cement. Through utilization of the device, the high-temperature high-pressure environment can be stimulated, and variation of the size of a crack is reflected through monitoring variation of the flow of the fluid passing through the crack of the cement rock in real time, so that a mending condition of the cement rock is reflected. Through utilization of the device, data can be collected through a computer, and variation of the flow with time is automatically observed and recorded in real time, so that a research worker can directly obtain data of a recorded result, and the workload of the research worker is relieved.