The invention relates to an ultrahigh pressure impulse steam turbine. The ultrahigh pressure impulse steam turbine comprises a single steam cylinder, a single rotor and multiple blade stages. The single steam cylinder is provided with a high pressure cylinder body and a middle-low pressure cylinder body. The single rotor is installed in the steam cylinder and stretches through the high pressure cylinder body and the middle-low pressure cylinder. Each blade stage comprises multiple stationary blades arranged on the inner wall of the steam cylinder and multiple moving blades arranged on the rotor. The steam cylinder comprises a high pressure cylinder steam inlet and a high pressure cylinder steam outlet which are located on the high pressure cylinder body, a high pressure intermediate-discharge extraction opening located on the high pressure cylinder body and a middle-low pressure cylinder steam inlet located on the middle-low pressure cylinder body. The high pressure cylinder steam inlet is directly communicated with the middle-low cylinder steam inlet through a connecting pipe. The ultrahigh pressure impulse steam turbine has the advantage that a large amount of industrial steam can be provided while electric power is generated.