The invention discloses a tube-type nanosecond high voltage steep pulse source, which comprises a high-voltage DC source, an input connector, a pulse transmission path, an operation switch and an output connector, wherein the input connector is composed of an input high voltage BNC joint and an input joint, the input high voltage BNC joint is connected with the high-voltage DC source, the output connector is composed of an output joint and an output high voltage BNC joint, the pulse transmission path is connected with the input joint and the output joint, the operation switch is arranged outside the pulse transmission path, and the pulse transmission path is provided with a wet reed tube for controlling output of the high voltage steep pulse source through control of the operation switch. The steep pulse source of the invention has a small size, is light in weight and can be used in a test device for measuring space charges by using a pulsed electroacoustic method; and as the wet reed tube is adopted for replacing a spark gap, the weight of the power supply is greatly reduced, and through test, nanosecond pulse voltage with a pulse width about 1ns and the highest amplitude of 2000V can be outputted.