The invention relates to a testing apparatus for special threaded oil casing tightness monitoring under the dynamic load working condition. The testing apparatus is characterized by comprising a bracket; the bracket comprises a pedestal, a hydraulic end bracket base, a fixed end bracket base and a fixed bracket base, and two sides of the top of the pedestal are respectively provided with the hydraulic end bracket base and the fixed end bracket base; the hydraulic end bracket base is provided with a hydraulic stretching apparatus, the fixed end bracket base is provided with a gas source connector, and the gas source connector is connected with a gas source pressurizing device; the hydraulic stretching apparatus is fixedly connected with one end of a to-be-tested oil tube sample, and the other end of the to-be-tested oil tube sample is fixedly connected with the gas source connector; the pedestal is also provided with a vibrating loading apparatus; and a control system is respectively inelectrical connection with the hydraulic stretching apparatus, the vibrating loading apparatus, a first pressure sensor, a second pressure sensor, a frequency sensor, a displacement sensor, a temperature sensor and a heater. The testing apparatus provided by the invention can be widely used in the field of high-temperature high-pressure oil-gas well oil casing tightness detection.