Abstract: The method of pumping killing fluid with different densities at high flow rate into blowout well through relief well is the first choice of well killing by relief well. This paper briefly sets forth the technical principle of dynamic well killing and provides the key points in dynamic well killing design and the method of equipment selection. The flow of dynamic well killing design was given in an example of one well, and the simulation of dynamic killing of multi-reservoir blowout was carried out under WCD (worst case discharge). The paper also gives the methods for selection of killing fluid density, platform equipment, etc. based on dynamic well killing. It is thought that the deepwater dynamic well killing design should take into account the fluid types of blowout well, blowout flow channels, wellbore flowrate under the effect of water depth, etc. Compared with conventional well killing method, deepwater dynamic well killing method is characterized by large displacement (max. up to 12 m3/min), high surface pump pressure (max. up to 26 MPa), large volume of required killing fluid (max. up to 2 100 m3), etc. All these can be used as a reference to the concept of design of dynamic well killing through relief well, drilling fluid pump on the platform, drilling fluid storage capacity, equipment selection, etc.