Abstract: Existing ultra-deep well overflow killing technology relies on engineers to manually control the throttle manifold, which has a slow response speed and large wellbore pressure fluctuation, and is easy to lead to complex situations such as secondary overflow and leakage, while automatic control of killing technology can provide the automated handling of overflow killing operations while drilling. Therefore, the automatic control method of proportional, integral and differential (PID) and displacement double-layer synergic feedback was designed. The automatic control killing system of ultra-deep well was developed, the physical simulation experiment device of automatic control killing was established, and the automatic control killing experiment was carried out under the conditions of constant target pressure, continuous change of target pressure and pressure sudden interference. The results show that the automatic control killing system can complete the adjustment of throttle valve opening in about 30s, and the range of throttle pressure fluctuation was less than 0.02 MPa. Compared with the manually controlled killing, the automatic control killing system has good stability, accuracy, response speed and anti-interference ability. The results of the study provide theoretical guidance for the safe compression of ultra-deep wells in complex formations.